Cycling

The Effect of Exercise Training on Resting Concentrations of Peripheral Brain-Derived Neurotrophic Factor (BDNF): A Meta-Analysis

Adam Dinoff, Nathan Herrmann, Walter Swardfager +4 more · PLoS ONE · 2016 · 325 citations

This meta-analysis found that consistent aerobic exercise training significantly increases resting levels of brain-derived neurotrophic factor (BDNF) in the blood, a protein linked to brain health and function, while resistance training does not.

World Health Organization 2020 guidelines on physical activity and sedentary behaviour

Fiona Bull, Salih S Al-Ansari, Stuart Biddle +27 more · British Journal of Sports Medicine · 2020 · 10,653 citations

This systematic review and guideline development process found that adults who do 150–300 minutes of moderate-intensity aerobic activity per week (or 75–150 minutes of vigorous activity) have a 20–30% lower risk of all-cause mortality, cardiovascular disease, type 2 diabetes, and several cancers compared to inactive adults, and that any amount of physical activity is better than none — making this the single most important evidence-based target for anyone running a personal health experiment.

Exercise and Physical Activity in the Prevention and Treatment of Atherosclerotic Cardiovascular Disease

Paul D. Thompson, David M. Büchner, Ileana L. Piña +13 more · Circulation · 2003 · 2,132 citations

Regular aerobic exercise (30+ minutes of moderate-intensity activity on most days) reduces the risk of developing coronary artery disease by approximately 50% in the most active versus most sedentary people, and exercise-based cardiac rehabilitation reduces mortality in patients with existing heart disease by roughly 20–30%.

A refined taxonomy of behaviour change techniques to help people change their physical activity and healthy eating behaviours: The CALO-RE taxonomy

Susan Michie, Stefanie Ashford, Falko F. Sniehotta +3 more · Psychology and Health · 2011 · 1,825 citations

This paper created a standardised, reliable list of 40 distinct behaviour change techniques (BCTs) for physical activity and healthy eating interventions, giving researchers and practitioners a common language to describe exactly what they did — so you can figure out which specific techniques actually work, rather than relying on vague labels like "counselling" or "motivational support."

International Exercise Recommendations in Older Adults (ICFSR): Expert Consensus Guidelines

Míkel Izquierdo, Reshma Aziz Merchant, John E. Morley +33 more · The journal of nutrition health & aging · 2021 · 1,126 citations

This expert consensus guideline synthesizes evidence from scientific studies to provide comprehensive, evidence-based recommendations for exercise and physical activity in older adults, aiming to prevent age-related decline, manage chronic diseases, and improve functional capacity.

The effect of fall prevention exercise programmes on fall induced injuries in community dwelling older adults

F El-Khoury, Bernard Cassou, Marie‐Aline Charles +1 more · British Journal of Sports Medicine · 2013 · 422 citations

Fall prevention exercise programmes for older adults living at home reduce the rate of injurious falls by 37%, and more importantly, cut the rate of fall-related fractures by 61% — meaning that if you're over 60 and worried about breaking a hip, starting a structured balance-and-strength exercise programme is one of the most effective things you can do.

Differential effects of endurance, interval, and resistance training on telomerase activity and telomere length in a randomized, controlled study

Christian Werner, Anne Hecksteden, Arne Morsch +10 more · European Heart Journal · 2018 · 199 citations

Endurance and high-intensity interval training (but not resistance training) increased telomerase activity by 2–3 fold and lengthened telomeres in immune cells over 6 months, suggesting that aerobic exercise may slow cellular aging in previously inactive adults.

Comparison of High-Intensity Interval Training and Moderate-to-Vigorous Continuous Training for Cardiometabolic Health and Exercise Enjoyment in Obese Young Women: A Randomized Controlled Trial

Zhaowei Kong, Xitao Fan, Shengyan Sun +3 more · PLoS ONE · 2016 · 184 citations

Both high-intensity interval training (HIIT) and moderate-to-vigorous continuous training (MVCT) improved cardiorespiratory fitness by about 9–10% over 5 weeks in obese young women, but HIIT was more enjoyable and required half the exercise time (20 minutes vs. 40 minutes per session), making it a time-efficient alternative for people who struggle with exercise adherence.

The major limitation to exercise performance in COPD is lower limb muscle dysfunction

Richard Debigaré, François Maltais · Journal of Applied Physiology · 2008 · 117 citations

POINT-COUNTERPOINTThe major limitation to exercise performance in COPD is lower limb muscle dysfunctionRichard Debigaré, and François MaltaisRichard Debigaré, and François MaltaisPublished Online:01 Aug 2008https://doi.org/10.1152/japplphysiol.90336.2008aMoreSectionsPDF (152 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations Exercise intolerance is ubiquitous in patients suffering from chronic obstructive pulmonary disease (COPD). Functional impairment can be evidenced by a lower walking capacity and cycling endurance compared with age-matched healthy controls (26). Reduced functional status and low level of daily physical activity predict poor quality of life (24), high health care use (7), and mortality (9) in these patients. A comprehensive understanding of the mechanisms of exercise intolerance is therefore of utmost importance to impact on these adverse outcomes and modify the evolution of the functional impairment associated with COPD.Respiratory impairment is not sufficient in itself to explain exercise intolerance in COPD. The weak correlation between FEV1 or inspiratory capacity and exercise tolerance implies that other factors must be involved (21, 14). In 1992, Killian and collaborators (15) published a landmark paper that draws attention to the impact of the lower limb muscles on exercise intolerance in COPD. They reported that leg discomfort was a frequent exercise-limiting symptom invoked by these patients after a standardized cycling protocol. This report was the foundation of the rationale used by scientists to investigate lower limb muscle dysfunction in COPD. At that time, no one could have predicted how vast this research area would develop.Although the ventilatory system is clearly dysfunctional in COPD, we will demonstrate that peripheral limitation to exercise tolerance is frequent in patients with COPD. To persuade the reader, morphological, biochemical, and clinical evidences demonstrating causal relationship between lower limb muscle dysfunction and exercise limitation will be exposed. We will focus on the tolerance to submaximal exercises, which are particularly influenced by the function and aerobic capacity of the lower limb muscles (3).Morphological and biochemical evidences of lower limb muscle dysfunction in COPD.The prevalence of lower limb muscle atrophy in COPD ranges from 21 to 45% depending on the population being investigated and its operational definition (23, 27). Unexpectedly, muscle atrophy can even be present in patients with normal body weight (27). Given that muscle strength is mostly determined by muscle mass, muscle weakness is therefore highly prevalent in COPD (4, 11). Patients with COPD also have a poor resistance to isolated leg exercises and increased susceptibility to muscle fatigue (16), two correlates of impaired exercise capacity (1). In parallel, altered muscle energy metabolism as assessed by 31phosphorus magnetic resonance spectroscopy (30) has also been correlated to reduced exercise capacity in patients with COPD (30).Muscle atrophy and impaired energy production are accountable for muscle weakness and increased susceptibility to fatigue, two strong determinants of exercise capacity (13). The physiological link between weakness, leg fatigue, and exercise intolerance was elegantly illustrated by Hamilton and colleagues (12). They evaluated the relationship between the perception of leg fatigue, work capacity, and muscle strength in normal individuals and patients with lung diseases, most of whom had COPD. Three interrelated observations, valid in healthy individuals and patients with lung diseases, were made 1) for a given power output, the perception of leg fatigue was greater in weaker compared with stronger individuals, 2) peak exercise capacity was reduced in weak individuals, and 3) the strength of the quadriceps was a key determinant of exercise capacity, independent of the impairment in lung function.Convincing biochemical data also support the thesis that lower limb muscle dysfunction is a major contributor to exercise intolerance in COPD. At the cellular level, several morphological and structural modifications have been observed in the quadriceps of patients with moderate to severe COPD (2). These changes substantially compromise the metabolic performance and work output of activated muscles during exercise. Specifically, the morphological changes observed include reduction in type I fiber proportion (28) as well as reduction in cross-sectional area (CSA) for type I and II fibers (10, 28) that is proportional to the reported reduction in mid-thigh cross-sectional area (4). This former observation suggests that contractile protein deficit is largely responsible for both muscle atrophy and weakness and thus contribute to impaired exercise capacity.The muscle structural and energetic changes described in COPD involve a reduction in myosin heavy chain I proportion (19) and a decrease in oxidative enzyme activities (10, 17, 18), a strong determinant of muscle endurance (1). Reduced oxidative metabolism correlates significantly with peak exercise capacity independently of lung function impairment (17). Early reliance on glycolytic activity for the energy production results in higher accumulation of inorganic phosphate (30) and premature muscle acidosis from lactate production (18), two biochemical events compromising the ability to sustain repeated muscle contractions and exercise performance. These adaptations seen in COPD are indicative of a muscle tissue that is inappropriately adapted to sustain the metabolic and mechanical requirements of submaximal exercises as seen in daily functional activities and provide a strong muscular basis to lower limb muscle dysfunction and exercise intolerance in COPD.Clinical evidences of lower limb muscle dysfunction in COPD.Exercise intolerance in COPD is the result of a complex interplay between central (ventilation, dynamic hyperinflation, dyspnea) and peripheral (muscle atrophy and weakness, fatigue) factors. Although the relative contribution of these components to exercise intolerance is difficult to sort out within a single patient, clinical models illustrating the role of the lower limb muscles are available.Undisputable evidences of peripheral limitation in exercising patients with COPD were provided by Williams and collaborators (29), who found that exercise limitation persisted in single and double lung transplant recipients years after the surgery despite complete restoration of their ventilatory capacity.Direct role of lower limb muscle dysfunction on exercise intolerance was evidenced by a study evaluating the impact of muscle fatigue on the exercise response to bronchodilation (22). In that study, the occurrence of contractile fatigue of the quadriceps after constant work rate cycling exercise prevented acute bronchodilation to translate into further improvement in exercise capacity. Patients with COPD complaining of leg fatigue as the main exercise-limiting symptom are also less likely to improve exercise tolerance following bronchodilation compared with those stopping because of dyspnea (8). These studies, together with the observation described above in lung transplantation, nicely illustrate how proximal peripheral limitation to exercise prevents interventions aimed at improving lung function to translate into better functional status.Pulmonary rehabilitation exemplifies how an intervention aimed at improving muscle function has a direct and significant positive impact on exercise tolerance. The consistent improvement in exercise tolerance reported with rehabilitation cannot be attributed to changes in respiratory function but rather to its global effects on lower limb muscle function characterized by improved strength, lesser susceptibility to fatigue, and better aerobic capacity (20). To some extent, these muscular physiological benefits also contribute to the reduction in ventilatory requirements, dynamic hyperinflation, and dyspnea often seen after exercise training (5, 6). In fact, better lower limb muscle function represents the physiological foundation of exercise training in COPD (25).Conclusion.Lower limb muscles in COPD are atrophied, weak, fatigable, and metabolically inefficient. These unfavorable muscle characteristics concur to limit exercise capacity, a most debilitating feature in COPD. Taken as a whole, clinical observation and research work performed in several laboratories support the notion that lower limb muscle dysfunction is largely responsible for exercise limitation in COPD. Denying this obvious concept and omitting this relevant component of the disease will disservice our patients since lower limb muscle dysfunction can be, in contrast to lung impairment, amenable to therapy by rehabilitative strategies.GRANTSF. Maltais and R. Debigaré are research scholars of the Fonds de la Recherche en Santé du Québec. This work was supported by CIHR Grant No. MOP-84091.REFERENCES1 Allaire J, Maltais F, Doyon JF, Noel M, Leblanc P, Carrier G, Simard C, Jobin J. Peripheral muscle endurance and the oxidative profile of the quadriceps in patients with COPD. Thorax 59: 673–678, 2004.Crossref | PubMed | ISI | Google Scholar2 American Thoracic Society/European Respiratory Society. Skeletal muscle dysfunction in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 159: S1–S40, 1999.Crossref | PubMed | ISI | Google Scholar3 Astrand PO, Rodahl K. Textbook of Work Physiology. Ohio: McGraw-Hill, 1970.Google Scholar4 Bernard S, Leblanc P, Whittom F, Carrier G, Jobin J, Belleau R, Maltais F. Peripheral muscle weakness in patients with chronic obstructive pulmonary disease. 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Eur Respir J 5: 157–162, 1992.PubMed | ISI | Google Scholar Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByEffect of modified Total Body Recumbent Stepper training on exercise capacity and thioredoxin in COPD: a randomized clinical trial1 July 2022 | Scientific Reports, Vol. 12, No. 1Ergogenic value of oxygen supplementation in chronic obstructive pulmonary disease12 July 2022 | Internal and Emergency Medicine, Vol. 17, No. 5Validity and reliability of a new incremental step test for people with chronic obstructive pulmonary disease6 April 2022 | BMJ Open Respiratory Research, Vol. 9, No. 1Impact of chronic obstructive pulmonary disease on passive viscoelastic components of the musculoarticular system10 September 2021 | Scientific Reports, Vol. 11, No. 1Severe loss of mechanical efficiency in COVID‐19 patients8 June 2021 | Journal of Cachexia, Sarcopenia and Muscle, Vol. 12, No. 4Acute Cardiopulmonary and Muscle Oxygenation Responses to Normocapnic Hyperpnea Exercise in COPDMedicine & Science in Sports & Exercise, Vol. Publish Ahead of PrintExtra-pulmonary manifestations of COPD and the role of pulmonary rehabilitation: a symptom-centered approach10 December 2020 | Expert Review of Respiratory Medicine, Vol. 15, No. 1Assessment of knowledge, attitude, and practice towards pulmonary rehabilitation among COPD patients: A multicenter and cross-sectional survey in ChinaRespiratory Medicine, Vol. 174More Impaired Dynamic Ventilatory Muscle Oxygenation in Congestive Heart Failure than in Chronic Obstructive Pulmonary Disease7 October 2019 | Journal of Clinical Medicine, Vol. 8, No. 10Personalized exercise training in chronic lung diseases3 July 2019 | Respirology, Vol. 24, No. 9Cardiopulmonary and Muscular Interactions: Potential Implications for Exercise (In)tolerance in Symptomatic Smokers Without Chronic Obstructive Pulmonary Disease10 July 2019 | Frontiers in Physiology, Vol. 10Long-acting bronchodilators improve exercise capacity in COPD patients: a systematic review and meta-analysis24 January 2018 | Respiratory Research, Vol. 19, No. 1Combination of inspiratory and expiratory muscle training in same respiratory cycle versus different cycles in COPD patients: a randomized trial20 November 2018 | Respiratory Research, Vol. 19, No. 1Physiological Responses and Dynamic Hyperinflation Induced by Unsupported Arm Activities Involved in Multiple-Task Activities of Daily Living Test in Patients With COPDJournal of Cardiopulmonary Rehabilitation and Prevention, Vol. 38, No. 6Near-infrared spectroscopy using indocyanine green dye for minimally invasive measurement of respiratory and leg muscle blood flow in patients with COPDZafeiris Louvaris, Helmut Habazettl, Harrieth Wagner, Spyros Zakynthinos, Peter Wagner, and Ioannis Vogiatzis27 September 2018 | Journal of Applied Physiology, Vol. 125, No. 3Chronic Obstructive Pulmonary Disease Education in Pulmonary Rehabilitation. 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The IOC consensus statement: beyond the Female Athlete Triad—Relative Energy Deficiency in Sport (RED-S)

Margo Mountjoy, Jorunn Sundgot‐Borgen, Louise M. Burke +8 more · British Journal of Sports Medicine · 2014 · 1,417 citations

Protecting the health of the athlete is a goal of the International Olympic Committee (IOC). The IOC convened an expert panel to update the 2005 IOC Consensus Statement on the Female Athlete Triad. This Consensus Statement replaces the previous and provides guidelines to guide risk assessment, treatment and return-to-play decisions. The IOC expert working group introduces a broader, more comprehensive term for the condition previously known as 'Female Athlete Triad'. The term 'Relative Energy Deficiency in Sport' (RED-S), points to the complexity involved and the fact that male athletes are also affected. The syndrome of RED-S refers to impaired physiological function including, but not limited to, metabolic rate, menstrual function, bone health, immunity, protein synthesis, cardiovascular health caused by relative energy deficiency. The cause of this syndrome is energy deficiency relative to the balance between dietary energy intake and energy expenditure required for health and activities of daily living, growth and sporting activities. Psychological consequences can either precede RED-S or be the result of RED-S. The clinical phenomenon is not a 'triad' of the three entities of energy availability, menstrual function and bone health, but rather a syndrome that affects many aspects of physiological function, health and athletic performance. This Consensus Statement also recommends practical clinical models for the management of affected athletes. The 'Sport Risk Assessment and Return to Play Model' categorises the syndrome into three groups and translates these classifications into clinical recommendations.

How much is too much? (Part 1) International Olympic Committee consensus statement on load in sport and risk of injury

Torbjørn Soligard, Martin Schwellnus, Juan Manuel Alonso +15 more · British Journal of Sports Medicine · 2016 · 967 citations

Athletes participating in elite sports are exposed to high training loads and increasingly saturated competition calendars. Emerging evidence indicates that poor load management is a major risk factor for injury. The International Olympic Committee convened an expert group to review the scientific evidence for the relationship of load (defined broadly to include rapid changes in training and competition load, competition calendar congestion, psychological load and travel) and health outcomes in sport. We summarise the results linking load to risk of injury in athletes, and provide athletes, coaches and support staff with practical guidelines to manage load in sport. This consensus statement includes guidelines for (1) prescription of training and competition load, as well as for (2) monitoring of training, competition and psychological load, athlete well-being and injury. In the process, we identified research priorities.

IOC consensus statement: dietary supplements and the high-performance athlete

Ronald J. Maughan, Louise M. Burke, Jiří Dvořák +22 more · British Journal of Sports Medicine · 2018 · 933 citations

Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete's health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.

Exercise and Type 2 Diabetes

Sheri R. Colberg, Ronald J. Sigal, Bo Fernhall +6 more · Diabetes Care · 2010 · 1,923 citations

Although physical activity (PA) is a key element in the prevention and management of type 2 diabetes, many with this chronic disease do not become or remain regularly active. High-quality studies establishing the importance of exercise and fitness in diabetes were lacking until recently, but it is now well established that participation in regular PA improves blood glucose control and can prevent or delay type 2 diabetes, along with positively affecting lipids, blood pressure, cardiovascular events, mortality, and quality of life. Structured interventions combining PA and modest weight loss have been shown to lower type 2 diabetes risk by up to 58% in high-risk populations. Most benefits of PA on diabetes management are realized through acute and chronic improvements in insulin action, accomplished with both aerobic and resistance training. The benefits of physical training are discussed, along with recommendations for varying activities, PA-associated blood glucose management, diabetes prevention, gestational diabetes mellitus, and safe and effective practices for PA with diabetes-related complications.

Exercise Standards for Testing and Training

Gerald F. Fletcher, Gary Balady, Ezra A. Amsterdam +10 more · Circulation · 2001 · 1,922 citations

T he purpose of this report is to provide revised standards and guidelines for the exercise testing and training of individuals who are free from clinical manifestations of cardiovascular disease and those with known cardiovascular disease. These guidelines are intended for physicians, nurses, exercise physiologists, specialists, technologists, and other healthcare professionals involved in exercise testing and training of these populations. This report is in accord with the "Statement on Exercise" published by the American Heart Association (AHA). An update of background, scientific rationale, and selected references is provided, and current issues of practical importance in the clinical use of these standards are considered. These guidelines are in accord with the American College of Cardiology (ACC)/AHA Guidelines for Exercise Testing. Specifically, all members of the writing group are required to complete and submit a Disclosure Questionnaire showing all such relationships that might be perceived as real or potential conflicts of interest.

Consensus on Exercise Reporting Template (CERT): Explanation and Elaboration Statement

Susan C. Slade, Clermont E. Dionne, Martin Underwood +1 more · British Journal of Sports Medicine · 2016 · 936 citations

Exercise is effective for prevention and management of acute and chronic health conditions. However, trial descriptions of exercise interventions are often suboptimal, leaving readers unclear about the content of effective programmes. To address this, the 16-item internationally endorsed Consensus on Exercise Reporting Template (CERT) was developed. The aim is to present the final template and provide an Explanation and Elaboration Statement to operationalise the CERT. Development of the CERT was based on the EQUATOR Network methodological framework for developing reporting guidelines. We used a modified Delphi technique to gain consensus of international exercise experts and conducted 3 sequential rounds of anonymous online questionnaires and a Delphi workshop. The 16-item CERT is the minimum data set considered necessary to report exercise interventions. The contents may be included in online supplementary material, published as a protocol or located on websites and other electronic repositories. The Explanation and Elaboration Statement is intended to enhance the use, understanding and dissemination of the CERT and presents the meaning and rationale for each item, together with examples of good reporting. The CERT is designed specifically for the reporting of exercise programmes across all evaluative study designs for exercise research. The CERT can be used by authors to structure intervention reports, by reviewers and editors to assess completeness of exercise descriptions and by readers to facilitate the use of the published information. The CERT has the potential to increase clinical uptake of effective exercise programmes, enable research replication, reduce research waste and improve patient outcomes.

Interval Training for Cardiometabolic Health: Why Such A HIIT?

Martin J. Gibala · Current Sports Medicine Reports · 2018 · 35 citations

High-intensity interval training (HIIT) improves cardiorespiratory fitness and several cardiometabolic risk factors as well as or better than traditional moderate-intensity continuous training (MICT), despite requiring 40–80% less total exercise time, with improvements in VO₂max of ~19% (about 2 metabolic equivalents) achievable in 6–12 weeks.

Computational Fluid Dynamics for urban physics: Importance, scales, possibilities, limitations and ten tips and tricks towards accurate and reliable simulations

Bert Blocken · Building and Environment · 2015 · 1,057 citations

Validity Evaluation of the Fitbit Charge2 and the Garmin vivosmart HR+ in Free-Living Environments in an Older Adult Cohort

Salvatore Tedesco, Marco Sica, Andrea Ancillao +3 more · JMIR mhealth and uhealth · 2019 · 149 citations

BACKGROUND: Few studies have investigated the validity of mainstream wrist-based activity trackers in healthy older adults in real life, as opposed to laboratory settings. OBJECTIVE: This study explored the performance of two wrist-worn trackers (Fitbit Charge 2 and Garmin vivosmart HR+) in estimating steps, energy expenditure, moderate-to-vigorous physical activity (MVPA) levels, and sleep parameters (total sleep time [TST] and wake after sleep onset [WASO]) against gold-standard technologies in a cohort of healthy older adults in a free-living environment. METHODS: Overall, 20 participants (>65 years) took part in the study. The devices were worn by the participants for 24 hours, and the results were compared against validated technology (ActiGraph and New-Lifestyles NL-2000i). Mean error, mean percentage error (MPE), mean absolute percentage error (MAPE), intraclass correlation (ICC), and Bland-Altman plots were computed for all the parameters considered. RESULTS: For step counting, all trackers were highly correlated with one another (ICCs>0.89). Although the Fitbit tended to overcount steps (MPE=12.36%), the Garmin and ActiGraph undercounted (MPE 9.36% and 11.53%, respectively). The Garmin had poor ICC values when energy expenditure was compared against the criterion. The Fitbit had moderate-to-good ICCs in comparison to the other activity trackers, and showed the best results (MAPE=12.25%), although it underestimated calories burned. For MVPA levels estimation, the wristband trackers were highly correlated (ICC=0.96); however, they were moderately correlated against the criterion and they overestimated MVPA activity minutes. For the sleep parameters, the ICCs were poor for all cases, except when comparing the Fitbit with the criterion, which showed moderate agreement. The TST was slightly overestimated with the Fitbit, although it provided good results with an average MAPE equal to 10.13%. Conversely, WASO estimation was poorer and was overestimated by the Fitbit but underestimated by the Garmin. Again, the Fitbit was the most accurate, with an average MAPE of 49.7%. CONCLUSIONS: The tested well-known devices could be adopted to estimate steps, energy expenditure, and sleep duration with an acceptable level of accuracy in the population of interest, although clinicians should be cautious in considering other parameters for clinical and research purposes.

Aerobic exercise intensity assessment and prescription in cardiac rehabilitation: a joint position statement of the European Association for Cardiovascular Prevention and Rehabilitation, the American Association of Cardiovascular and Pulmonary Rehabilitation and the Canadian Association of Cardiac Rehabilitation

Alessandro Mezzani, Larry F. Hamm, Andrew M. Jones +5 more · European Journal of Preventive Cardiology · 2012 · 545 citations

Aerobic exercise intensity prescription is a key issue in cardiac rehabilitation, being directly linked to both the amount of improvement in exercise capacity and the risk of adverse events during exercise. This joint position statement aims to provide professionals with up-to-date information regarding the identification of different exercise intensity domains, the methods of direct and indirect determination of exercise intensity for both continuous and interval aerobic training, the effects of the use of different exercise protocols on exercise intensity prescription and the indications for recommended exercise training prescription in specific cardiac patients' groups. The importance of functional evaluation through exercise testing prior to starting an aerobic training program is strongly emphasized, and ramp incremental cardiopulmonary exercise test, when available, is proposed as the gold standard for a physiologically comprehensive exercise intensity assessment and prescription. This may allow a shift from a 'range-based' to a 'threshold-based' aerobic exercise intensity prescription, which, combined with thorough clinical evaluation and exercise-related risk assessment, could maximize the benefits obtainable by the use of aerobic exercise training in cardiac rehabilitation.

IOC Consensus Statement: Dietary Supplements and the High-Performance Athlete

Ronald J. Maughan, Louise M. Burke, Jiří Dvořák +22 more · International Journal of Sport Nutrition and Exercise Metabolism · 2018 · 506 citations

Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete’s health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete’s health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.

CROSSOVER COMPARISON BETWEEN THE DEPRESSOR EFFECTS OF LOW AND HIGH WORK‐RATE EXERCISE IN MILD HYPERTENSION

Eiichiro Tashiro, Shin‐ichiro Miura, Manabu Koga +6 more · Clinical and Experimental Pharmacology and Physiology · 1993 · 46 citations

1. The relationship between work-rate and the antihypertensive effect of exercise in hypertensives, and the mechanism of that effect, were investigated by a crossover clinical trial. 2. Ten mild hypertensives were randomly divided into two groups. One group performed low work-rate exercise (LWE) on a cycle ergometer for 10 weeks (blood lactate threshold; approximately 50% of maximum oxygen consumption [Vo2max]). After a 10 week interval without exercise training, these subjects were then switched to a high work-rate exercise (HWE) regimen (4 mmol/L of blood lactate; approximately 75% of Vo2max) for another 10 weeks. In the other group, the order of exercise training was reversed. Since two patients withdrew from the protocol during HWE periods, statistical analysis was performed on the data from the remaining eight patients. There were no order effects observed in any of the data from the two groups. 3. During both LWE and HWE, resting blood pressure (BP) fell significantly after the initiation of exercise therapy (P < 0.05). Furthermore, the overall effects of 10 weeks of LWE and HWE on BP were not significantly different. 4. The work-rate at the lactate threshold, which reflects physical fitness, had increased significantly by 16 W (P < 0.01) after the LWE period and by 11 W (P < 0.01) after the HWE. 5. During the LWE period, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 10 (P < 0.05). In the HWE period, changes in haemodynamic and humoral variables were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

A Perspective on High-Intensity Interval Training for Performance and Health

Alexandra M. Coates, Michael J. Joyner, Jonathan P. Little +2 more · Sports Medicine · 2023 · 196 citations

Interval training is a simple concept that refers to repeated bouts of relatively hard work interspersed with recovery periods of easier work or rest. The method has been used by high-level athletes for over a century to improve performance in endurance-type sports and events such as middle- and long-distance running. The concept of interval training to improve health, including in a rehabilitative context or when practiced by individuals who are relatively inactive or deconditioned, has also been advanced for decades. An important issue that affects the interpretation and application of interval training is the lack of standardized terminology. This particularly relates to the classification of intensity. There is no common definition of the term "high-intensity interval training" (HIIT) despite its widespread use. We contend that in a performance context, HIIT can be characterized as intermittent exercise bouts performed above the heavy-intensity domain. This categorization of HIIT is primarily encompassed by the severe-intensity domain. It is demarcated by indicators that principally include the critical power or critical speed, or other indices, including the second lactate threshold, maximal lactate steady state, or lactate turnpoint. In a health context, we contend that HIIT can be characterized as intermittent exercise bouts performed above moderate intensity. This categorization of HIIT is primarily encompassed by the classification of vigorous intensity. It is demarcated by various indicators related to perceived exertion, oxygen uptake, or heart rate as defined in authoritative public health and exercise prescription guidelines. A particularly intense variant of HIIT commonly termed "sprint interval training" can be distinguished as repeated bouts performed with near-maximal to "all out" effort. This characterization coincides with the highest intensity classification identified in training zone models or exercise prescription guidelines, including the extreme-intensity domain, anaerobic speed reserve, or near-maximal to maximal intensity classification. HIIT is considered an essential training component for the enhancement of athletic performance, but the optimal intensity distribution and specific HIIT prescription for endurance athletes is unclear. HIIT is also a viable method to improve cardiorespiratory fitness and other health-related indices in people who are insufficiently active, including those with cardiometabolic diseases. Research is needed to clarify responses to different HIIT strategies using robust study designs that employ best practices. We offer a perspective on the topic of HIIT for performance and health, including a conceptual framework that builds on the work of others and outlines how the method can be defined and operationalized within each context.

Following a Long-Distance Classical Race the Whole-Body Kinematics of Double Poling by Elite Cross-Country Skiers Are Altered

Chiara Zoppirolli, Lorenzo Bortolan, Federico Stella +4 more · Frontiers in Physiology · 2018 · 348 citations

Prolonged DP reduced the forward displacement of the COM and altered arm kinematics during the early poling phase. The inefficient utilization of COM observed after 2 h of competition together with potential impairment of the stretch-shortening of arm extensor muscles probably attenuated generation of poling force. To minimize these effects of fatigue, elite skiers should focus on maintaining optimal elbow and ankle kinematics and an effective forward lean during the propulsive phase of DP.

Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training despite a Five-Fold Lower Exercise Volume and Time Commitment

Jenna B. Gillen, Brian J. Martin, Martin J. MacInnis +3 more · PLoS ONE · 2016 · 341 citations

AIMS: We investigated whether sprint interval training (SIT) was a time-efficient exercise strategy to improve insulin sensitivity and other indices of cardiometabolic health to the same extent as traditional moderate-intensity continuous training (MICT). SIT involved 1 minute of intense exercise within a 10-minute time commitment, whereas MICT involved 50 minutes of continuous exercise per session. METHODS: Sedentary men (27±8y; BMI = 26±6kg/m2) performed three weekly sessions of SIT (n = 9) or MICT (n = 10) for 12 weeks or served as non-training controls (n = 6). SIT involved 3x20-second 'all-out' cycle sprints (~500W) interspersed with 2 minutes of cycling at 50W, whereas MICT involved 45 minutes of continuous cycling at ~70% maximal heart rate (~110W). Both protocols involved a 2-minute warm-up and 3-minute cool-down at 50W. RESULTS: Peak oxygen uptake increased after training by 19% in both groups (SIT: 32±7 to 38±8; MICT: 34±6 to 40±8ml/kg/min; p<0.001 for both). Insulin sensitivity index (CSI), determined by intravenous glucose tolerance tests performed before and 72 hours after training, increased similarly after SIT (4.9±2.5 to 7.5±4.7, p = 0.002) and MICT (5.0±3.3 to 6.7±5.0 x 10-4 min-1 [μU/mL]-1, p = 0.013) (p<0.05). Skeletal muscle mitochondrial content also increased similarly after SIT and MICT, as primarily reflected by the maximal activity of citrate synthase (CS; P<0.001). The corresponding changes in the control group were small for VO2peak (p = 0.99), CSI (p = 0.63) and CS (p = 0.97). CONCLUSIONS: Twelve weeks of brief intense interval exercise improved indices of cardiometabolic health to the same extent as traditional endurance training in sedentary men, despite a five-fold lower exercise volume and time commitment.

Physical Activity and Exercise Recommendations for Stroke Survivors

Neil F. Gordon, Meg Gulanick, Fernando Costa +4 more · Circulation · 2004 · 500 citations

HomeCirculationVol. 109, No. 16Physical Activity and Exercise Recommendations for Stroke Survivors

Consensus recommendations on training and competing in the heat

Sébastien Racinais, Juan Manuel Alonso, Aaron J. Coutts +14 more · British Journal of Sports Medicine · 2015 · 329 citations

Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide up-to-date recommendations to optimise performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimise performance is to heat acclimatise. Heat acclimatisation should comprise repeated exercise-heat exposures over 1-2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimise dehydration during exercise. Following the development of commercial cooling systems (eg, cooling-vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organisers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimising the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events, for hydration and body cooling opportunities, when competitions are held in the heat.

Review on Wearable Technology in Sports: Concepts, Challenges and Opportunities

Ahmet Çağdaş Seçkin, Bahar Ateş, Mine Seçkin · Applied Sciences · 2023 · 222 citations

Wearable technology is increasingly vital for improving sports performance through real-time data analysis and tracking. Both professional and amateur athletes rely on wearable sensors to enhance training efficiency and competition outcomes. However, further research is needed to fully understand and optimize their potential in sports. This comprehensive review explores the measurement and monitoring of athletic performance, injury prevention, rehabilitation, and overall performance optimization using body wearable sensors. By analyzing wearables’ structure, research articles across various sports, and commercial sensors, the review provides a thorough analysis of wearable sensors in sports. Its findings benefit athletes, coaches, healthcare professionals, conditioners, managers, and researchers, offering a detailed summary of wearable technology in sports. The review is expected to contribute to future advancements in wearable sensors and biometric data analysis, ultimately improving sports performance. Limitations such as privacy concerns, accuracy issues, and costs are acknowledged, stressing the need for legal regulations, ethical principles, and technical measures for safe and fair use. The importance of personalized devices and further research on athlete comfort and performance impact is emphasized. The emergence of wearable imaging devices holds promise for sports rehabilitation and performance monitoring, enabling enhanced athlete health, recovery, and performance in the sports industry.

Significant Molecular and Systemic Adaptations after Repeated Sprint Training in Hypoxia

Raphaël Faiss, Bertrand Léger, Jean-Marc Vésin +4 more · PLoS ONE · 2013 · 281 citations

While intermittent hypoxic training (IHT) has been reported to evoke cellular responses via hypoxia inducible factors (HIFs) but without substantial performance benefits in endurance athletes, we hypothesized that repeated sprint training in hypoxia could enhance repeated sprint ability (RSA) performed in normoxia via improved glycolysis and O(2) utilization. 40 trained subjects completed 8 cycling repeated sprint sessions in hypoxia (RSH, 3000 m) or normoxia (RSN, 485 m). Before (Pre-) and after (Post-) training, muscular levels of selected mRNAs were analyzed from resting muscle biopsies and RSA tested until exhaustion (10-s sprint, work-to-rest ratio 1:2) with muscle perfusion assessed by near-infrared spectroscopy. From Pre- to Post-, the average power output of all sprints in RSA was increased (p<0.01) to the same extent (6% vs 7%, NS) in RSH and in RSN but the number of sprints to exhaustion was increased in RSH (9.4±4.8 vs. 13.0±6.2 sprints, p<0.01) but not in RSN (9.3±4.2 vs. 8.9±3.5). mRNA concentrations of HIF-1α (+55%), carbonic anhydrase III (+35%) and monocarboxylate transporter-4 (+20%) were augmented (p<0.05) whereas mitochondrial transcription factor A (-40%), peroxisome proliferator-activated receptor gamma coactivator 1α (-23%) and monocarboxylate transporter-1 (-36%) were decreased (p<0.01) in RSH only. Besides, the changes in total hemoglobin variations (Δ[tHb]) during sprints throughout RSA test increased to a greater extent (p<0.01) in RSH. Our findings show larger improvement in repeated sprint performance in RSH than in RSN with significant molecular adaptations and larger blood perfusion variations in active muscles.

Integrated Assessment of Urban Overheating Impacts on Human Life

Negin Nazarian, E. Scott Krayenhoff, Benjamin Bechtel +14 more · Earth s Future · 2022 · 202 citations

Abstract Urban overheating, driven by global climate change and urban development, is a major contemporary challenge that substantially impacts urban livability and sustainability. Overheating represents a multifaceted threat to the well‐being, performance, and health of individuals as well as the energy efficiency and economy of cities, and it is influenced by complex interactions between building, city, and global scale climates. In recent decades, extensive discipline‐specific research has characterized urban heat and assessed its implications on human life, including ongoing efforts to bridge neighboring disciplines. The research horizon now encompasses complex problems involving a wide range of disciplines, and therefore comprehensive and integrated assessments are needed that address such interdisciplinarity. Here, our objective is to go beyond a review of existing literature and instead provide a broad overview and integrated assessments of urban overheating, defining holistic pathways for addressing the impacts on human life. We (a) detail the characterization of heat hazards and exposure across different scales and in various disciplines, (b) identify individual sensitivities to urban overheating that increase vulnerability and cause adverse impacts in different populations, (c) elaborate on adaptive capacities that individuals and cities can adopt, (d) document the impacts of urban overheating on health and energy, and (e) discuss frontiers of theoretical and applied urban climatology, built environment design, and governance toward reduction of heat exposure and vulnerability at various scales. The most critical challenges in future research and application are identified, targeting both the gaps and the need for greater integration in overheating assessments.

Effects of Exercise Training on Left Ventricular Function and Peripheral Resistance in Patients With Chronic Heart Failure

Rainer Hambrecht · JAMA · 2000 · 684 citations

CONTEXT: Exercise training in patients with chronic heart failure improves work capacity by enhancing endothelial function and skeletal muscle aerobic metabolism, but effects on central hemodynamic function are not well established. OBJECTIVE: To evaluate the effects of exercise training on left ventricular (LV) function and hemodynamic response to exercise in patients with stable chronic heart failure. DESIGN: Prospective randomized trial conducted in 1994-1999. SETTING: University department of cardiology/outpatient clinic in Germany. PATIENTS: Consecutive sample of 73 men aged 70 years or younger with chronic heart failure (with LV ejection fraction of approximately 0.27). INTERVENTION: Patients were randomly assigned to 2 weeks of in-hospital ergometer exercise for 10 minutes 4 to 6 times per day, followed by 6 months of home-based ergometer exercise training for 20 minutes per day at 70% of peak oxygen uptake (n=36) or to no intervention (control group; n=37). MAIN OUTCOME MEASURES: Ergospirometry with measurement of central hemodynamics by thermodilution at rest and during exercise; echocardiographic determination of LV diameters and volumes, at baseline and 6-month follow-up, for the exercise training vs control groups. RESULTS: After 6 months, patients in the exercise training group had statistically significant improvements compared with controls in New York Heart Association functional class, maximal ventilation, exercise time, and exercise capacity as well as decreased resting heart rate and increased stroke volume at rest. In the exercise training group, an increase from baseline to 6-month follow-up was observed in mean (SD) resting LV ejection fraction (0.30 [0.08] vs 0.35 [0.09]; P=.003). Mean (SD) total peripheral resistance (TPR) during peak exercise was reduced by 157 (306) dyne/s/cm(-5) in the exercise training group vs an increase of 43 (148) dyne/s/cm(-5) in the control group (P=.003), with a concomitant increase in mean (SD) stroke volume of 14 (22) mL vs 1 (19) mL in the control group (P=.03). There was a small but significant reduction in mean (SD) LV end diastolic diameter of 4 (6) mm vs an increase of 1 (4) mm in the control group (P<.001). Changes from baseline in resting TPR for both groups were correlated with changes in stroke volume (r=-0.76; P<.001) and in LV end diastolic diameter (r=0.45; P<.001). CONCLUSIONS: In patients with stable chronic heart failure, exercise training is associated with reduction of peripheral resistance and results in small but significant improvements in stroke volume and reduction in cardiomegaly. JAMA. 2000.

The Road to Gold: Training and Peaking Characteristics in the Year Prior to a Gold Medal Endurance Performance

Espen Tønnessen, Øystein Sylta, Thomas Haugen +3 more · PLoS ONE · 2014 · 248 citations

PURPOSE: To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature. METHODS: Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL x min(-1) x kg(-1) VO2max, 7 female, 25±4 yr, 73±3 mL x min(-1) x kg(-1) VO2max) reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms. RESULTS: Athletes trained ∼800 h/500 sessions x year(-1), including ∼500 h x year(-1) of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold) and 10% high intensity training (HIT, above the first lactate threshold) by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (P<.01) volume reduction from the preparation period to peaking phase. CONCLUSIONS: The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to their most successful competition.

Running in a minimalist and lightweight shoe is not the same as running barefoot: a biomechanical study

Jason Bonacci, Philo U. Saunders, Amy Hicks +3 more · British Journal of Sports Medicine · 2013 · 248 citations

AIM: The purpose of this study was to determine the changes in running mechanics that occur when highly trained runners run barefoot and in a minimalist shoe, and specifically if running in a minimalist shoe replicates barefoot running. METHODS: Ground reaction force data and kinematics were collected from 22 highly trained runners during overground running while barefoot and in three shod conditions (minimalist shoe, racing flat and the athlete's regular shoe). Three-dimensional net joint moments and subsequent net powers and work were computed using Newton-Euler inverse dynamics. Joint kinematic and kinetic variables were statistically compared between barefoot and shod conditions using a multivariate analysis of variance for repeated measures and standardised mean differences calculated. RESULTS: There were significant differences between barefoot and shod conditions for kinematic and kinetic variables at the knee and ankle, with no differences between shod conditions. Barefoot running demonstrated less knee flexion during midstance, an 11% decrease in the peak internal knee extension and abduction moments and a 24% decrease in negative work done at the knee compared with shod conditions. The ankle demonstrated less dorsiflexion at initial contact, a 14% increase in peak power generation and a 19% increase in the positive work done during barefoot running compared with shod conditions. CONCLUSIONS: Barefoot running was different to all shod conditions. Barefoot running changes the amount of work done at the knee and ankle joints and this may have therapeutic and performance implications for runners.

Physical Activity and Diabetes

Ronald J. Sigal, Marni J. Armstrong, Simon Bacon +4 more · Canadian Journal of Diabetes · 2018 · 243 citations

Consensus recommendations on training and competing in the heat

Sébastien Racinais, Juan Manuel Alonso, Aaron J. Coutts +14 more · Scandinavian Journal of Medicine and Science in Sports · 2015 · 243 citations

Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide up-to-date recommendations to optimize performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimize performance is to heat acclimatize. Heat acclimatization should comprise repeated exercise-heat exposures over 1-2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimize dehydration during exercise. Following the development of commercial cooling systems (e.g., cooling vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organizers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimizing the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events for hydration and body cooling opportunities when competitions are held in the heat.

Initial Manifestations of Frailty Criteria and the Development of Frailty Phenotype in the Women's Health and Aging Study II

Qian‐Li Xue, Karen Bandeen‐Roche, Ravi Varadhan +2 more · The Journals of Gerontology Series A · 2008 · 484 citations

BACKGROUND: Understanding points of onset of the frailty syndrome is vital to early identification of at-risk individuals and to targeting intervention efforts to those components that are first affected, when reversal may be most possible. This study aims to characterize natural history by which commonly used frailty criteria manifest and to assess whether the rate of progression to frailty depends on initial manifestations. METHODS: The investigation was based on a 7.5-year observational study of 420 community-dwelling women aged 70-79 years who were not frail at baseline, with frailty defined as meeting>or=3 of 5 criteria: weight loss, slow walking speed, weakness, exhaustion, and low physical activity level. RESULTS: The 7.5-year incidence of frailty was 9% among women who were nonfrail at baseline. Despite significant heterogeneity, weakness was the most common first manifestation, and occurrence of weakness, slowness, and low physical activity preceded exhaustion and weight loss in 76% of the women who were nonfrail at baseline. Women with exhaustion or weight loss as initial presenting symptoms were 3-5 times more likely to become frail than were women without any criterion (p<.05). CONCLUSIONS: Our findings suggest that weakness may serve as a warning sign of increasing vulnerability in early frailty development, and weight loss and exhaustion may help to identify women most at risk for rapid adverse progression.

The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity.

Carl Foster, Courtney Farland, Flavia Guidotti +6 more · PubMed · 2015 · 209 citations

UNLABELLED: High intensity interval training (HIIT) has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement. This study compared the effects of two HIIT protocols vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training. Fifty-five untrained college-aged subjects were randomly assigned to three training groups (3x weekly). Steady-state (n = 19) exercised (cycle ergometer) 20 minutes at 90% of ventilatory threshold (VT). Tabata (n = 21) completed eight intervals of 20s at 170% VO2max/10s rest. Meyer (n = 15) completed 13 sets of 30s (20 min) @ 100% PVO2 max/ 60s recovery, average PO = 90% VT. Each subject did 24 training sessions during 8 weeks. RESULTS: There were significant (p < 0.05) increases in VO2max (+19, +18 and +18%) and PPO (+17, +24 and +14%) for each training group, as well as significant increases in peak (+8, + 9 and +5%) & mean (+4, +7 and +6%) power during Wingate testing, but no significant differences between groups. Measures of the enjoyment of the training program indicated that the Tabata protocol was significantly less enjoyable (p < 0.05) than the steady state and Meyer protocols, and that the enjoyment of all protocols declined (p < 0.05) across the duration of the study. The results suggest that although HIIT protocols are time efficient, they are not superior to conventional exercise training in sedentary young adults. Key pointsSteady state training equivalent to HIIT in untrained studentsMild interval training presents very similar physiologic challenge compared to steady state trainingHIIT (particularly very high intensity variants were less enjoyable than steady state or mild interval trainingEnjoyment of training decreases across the course of an 8 week experimental training program.

The Role of Daylight for Humans: Gaps in Current Knowledge

Mirjam Münch, Anna Wirz‐Justice, Steven A. Brown +7 more · Clocks & Sleep · 2020 · 153 citations

Daylight stems solely from direct, scattered and reflected sunlight, and undergoes dynamic changes in irradiance and spectral power composition due to latitude, time of day, time of year and the nature of the physical environment (reflections, buildings and vegetation). Humans and their ancestors evolved under these natural day/night cycles over millions of years. Electric light, a relatively recent invention, interacts and competes with the natural light-dark cycle to impact human biology. What are the consequences of living in industrialised urban areas with much less daylight and more use of electric light, throughout the day (and at night), on general health and quality of life? In this workshop report, we have classified key gaps of knowledge in daylight research into three main groups: (I) uncertainty as to daylight quantity and quality needed for "optimal" physiological and psychological functioning, (II) lack of consensus on practical measurement and assessment methods and tools for monitoring real (day) light exposure across multiple time scales, and (III) insufficient integration and exchange of daylight knowledge bases from different disciplines. Crucial short and long-term objectives to fill these gaps are proposed.

Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body

Stephan van der Zwaard, Willem J. van der Laarse, Guido Weide +7 more · The FASEB Journal · 2017 · 75 citations

Optimizing physical performance is a major goal in current physiology. However, basic understanding of combining high sprint and endurance performance is currently lacking. This study identifies critical determinants of combined sprint and endurance performance using multiple regression analyses of physiologic determinants at different biologic levels. Cyclists, including 6 international sprint, 8 team pursuit, and 14 road cyclists, completed a Wingate test and 15‐km time trial to obtain sprint and endurance performance results, respectively. Performance was normalized to lean body mass 2/3 to eliminate the influence of body size. Performance determinants were obtained from whole‐body oxygen consumption, blood sampling, knee‐extensor maximal force, muscle oxygenation, whole‐muscle morphology, and muscle fiber histochemistry of musculus vastus lateralis. Normalized sprint performance was explained by percentage of fast‐type fibers and muscle volume ( R 2 = 0.65; P &lt; 0.001) and normalized endurance performance by performance oxygen consumption (Vo 2 ), mean corpuscular hemoglobin concentration, and muscle oxygenation ( R 2 = 0.92; P &lt; 0.001). Combined sprint and endurance performance was explained by gross efficiency, performance Vo 2 and likely by muscle volume and fascicle length ( P = 0.056; P = 0.059). High performance Vo 2 related to a high oxidative capacity, high capillarization x myoglobin, and small physiologic cross‐sectional area ( R 2 = 0.67; P &lt; 0.001). Results suggest that fascicle length and capillarization are important targets for training to optimize sprint and endurance performance simultaneously.— Van der Zwaard, S., van derLaarse, W. J., Weide, G., Bloemers, F. W., Hofmijster, M. J., Levels, K., Noordhof, D. A., de Koning, J. J., de Ruiter, C. J., Jaspers, R. T. Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body. FASEB J. 32, 2110–2123 (2018). www.fasebj.org

International Olympic Committee consensus statement on thermoregulatory and altitude challenges for high-level athletes

MF Bergeron, Roald Bahr, Peter Bärtsch +15 more · British Journal of Sports Medicine · 2012 · 206 citations

Challenging environmental conditions, including heat and humidity, cold, and altitude, pose particular risks to the health of Olympic and other high-level athletes. As a further commitment to athlete safety, the International Olympic Committee (IOC) Medical Commission convened a panel of experts to review the scientific evidence base, reach consensus, and underscore practical safety guidelines and new research priorities regarding the unique environmental challenges Olympic and other international-level athletes face. For non-aquatic events, external thermal load is dependent on ambient temperature, humidity, wind speed and solar radiation, while clothing and protective gear can measurably increase thermal strain and prompt premature fatigue. In swimmers, body heat loss is the direct result of convection at a rate that is proportional to the effective water velocity around the swimmer and the temperature difference between the skin and the water. Other cold exposure and conditions, such as during Alpine skiing, biathlon and other sliding sports, facilitate body heat transfer to the environment, potentially leading to hypothermia and/or frostbite; although metabolic heat production during these activities usually increases well above the rate of body heat loss, and protective clothing and limited exposure time in certain events reduces these clinical risks as well. Most athletic events are held at altitudes that pose little to no health risks; and training exposures are typically brief and well-tolerated. While these and other environment-related threats to performance and safety can be lessened or averted by implementing a variety of individual and event preventative measures, more research and evidence-based guidelines and recommendations are needed. In the mean time, the IOC Medical Commission and International Sport Federations have implemented new guidelines and taken additional steps to mitigate risk even further.

Human adaptation to high altitude: Regional and life-cycle perspectives

Lorna G. Moore, Susan Niermeyer, Stacy Zamudio · American Journal of Physical Anthropology · 1998 · 374 citations

Studies of the ways in which persons respond to the adaptive challenges of life at high altitude have occupied an important place in anthropology. There are three major regions of the world where high-altitude studies have recently been performed: the Himalayas of Asia, the Andes of South America, and the Rocky Mountains of North America. Of these, the Himalayan region is larger, more geographically remote, and likely to have been occupied by humans for a longer period of time and to have been subject to less admixture or constriction of its gene pool. Recent studies of the physiological responses to hypoxia across the life cycle in these groups reveal several differences in adaptive success. Compared with acclimatized newcomers, lifelong residents of the Andes and/or Himalayas have less intrauterine growth retardation, better neonatal oxygenation, and more complete neonatal cardiopulmonary transition, enlarged lung volumes, decreased alveolar-arterial oxygen diffusion gradients, and higher maximal exercise capacity. In addition, Tibetans demonstrate a more sustained increase in cerebral blood flow during exercise, lower hemoglobin concentration, and less susceptibility to chronic mountain sickness (CMS) than acclimatized newcomers. Compared to Andean or Rocky Mountain high-altitude residents, Tibetans demonstrate less intrauterine growth retardation, greater reliance on redistribution of blood flow than elevated arterial oxygen content to increase uteroplacental oxygen delivery during pregnancy, higher levels of resting ventilation and hypoxic ventilatory responsiveness, less hypoxic pulmonary vasoconstriction, lower hemoglobin concentration, and less susceptibility to CMS. Several of the distinctions demonstrated by Tibetans parallel the differences between natives and newcomers, suggesting that the degree of protection or adaptive benefit relative to newcomers is enhanced for the Tibetans. We thus conclude that Tibetans have several physiological distinctions that confer adaptive benefit consistent with their probable greater generational length of high-altitude residence. Future progress is anticipated in achieving a more integrated view of high-altitude adaptation, incorporating a sophisticated understanding of the ways in which levels of biological organization are articulated and a recognition of the specific genetic variants contributing to differences among high-altitude groups.

Refuting the myth of non‐response to exercise training: ‘non‐responders’ do respond to higher dose of training

David Montero, Carsten Lundby · The Journal of Physiology · 2017 · 315 citations

KEY POINTS: The prevalence of cardiorespiratory fitness (CRF) non-response gradually declines in healthy individuals exercising 60, 120, 180, 240 or 300 min per week for 6 weeks. Following a successive identical 6-week training period but comprising 120 min of additional exercise per week, CRF non-response is universally abolished. The magnitude of CRF improvement is primarily attributed to changes in haemoglobin mass. The potential for CRF improvement may be present and unveiled with appropriate exercise training stimuli in healthy individuals without exception. ABSTRACT: = 0.49, P < 0.001). In conclusion, individual CRF non-response to exercise training is abolished by increasing the dose of exercise and primarily a function of haematological adaptations in oxygen-carrying capacity.

Inter-Individual Variability in the Adaptive Responses to Endurance and Sprint Interval Training: A Randomized Crossover Study

Jacob T. Bonafiglia, Mario Rotundo, Jonathan Whittall +3 more · PLoS ONE · 2016 · 169 citations

The current study examined the adaptive response to both endurance (END) and sprint interval training (SIT) in a group of twenty-one recreationally active adults. All participants completed three weeks (four days/ week) of both END (30 minutes at ~65% VO2peak work rate (WR) and SIT (eight, 20-second intervals at ~170% VO2peak WR separated by 10 seconds of active rest) following a randomized crossover study design with a three-month washout period between training interventions. While a main effect of training was observed for VO2peak, lactate threshold, and submaximal heart rate (HR), considerable variability was observed in the individual responses to both END and SIT. No significant positive relationships were observed between END and SIT for individual changes in any variable. Non-responses were determined using two times the typical error (TE) of measurement for VO2peak (0.107 L/min), lactate threshold (15.7 W), and submaximal HR (10.7bpm). Non-responders in VO2peak, lactate threshold, and submaximal HR were observed following both END and SIT, however, the individual patterns of response differed following END and SIT. Interestingly, all individuals responded in at least one variable when exposed to both END and SIT. These results suggest that the individual response to exercise training is highly variable following different training protocols and that the incidence of non-response to exercise training may be reduced by changing the training stimulus for non-responders to three weeks of END or SIT.

Personal strategies to minimise effects of air pollution on respiratory health: advice for providers, patients and the public

Christopher Carlsten, Sundeep Salvi, Gary Wong +1 more · European Respiratory Journal · 2020 · 167 citations

As global awareness of air pollution rises, so does the imperative to provide evidence-based recommendations for strategies to mitigate its impact. While public policy has a central role in reducing air pollution, exposure can also be reduced by personal choices. Qualified evidence supports limiting physical exertion outdoors on high air pollution days and near air pollution sources, reducing near-roadway exposure while commuting, utilising air quality alert systems to plan activities, and wearing facemasks in prescribed circumstances. Other strategies include avoiding cooking with solid fuels, ventilating and isolating cooking areas, and using portable air cleaners fitted with high-efficiency particulate air filters. We detail recommendations to assist providers and public health officials when advising patients and the public regarding personal-level strategies to mitigate risk imposed by air pollution, while recognising that well-designed prospective studies are urgently needed to better establish and validate interventions that benefit respiratory health in this context.

Aerobic Capacity Reference Data in 3816 Healthy Men and Women 20–90 Years

Löe H, Øivind Rognmo, Bengt Saltin +1 more · PLoS ONE · 2013 · 214 citations

PURPOSE: To provide a large reference material on aerobic fitness and exercise physiology data in a healthy population of Norwegian men and women aged 20-90 years. METHODS: Maximal and sub maximal levels of VO2, heart rate, oxygen pulse, and rating of perceived exertion (Borg scale: 6-20) were measured in 1929 men and 1881 women during treadmill running. RESULTS: The highest VO2max and maximal heart rate among men and women were observed in the youngest age group (20-29 years) and was 54.4±8.4 mL·kg(-1)·min(-1) and 43.0±7.7 mL·kg(-1)·min(-1) (sex differences, p<0.001) and 196±10 beats·min(-1) and 194±9 beats·min(-1) (sex differences, p<0.05), respectively, with a subsequent reduction of approximately 3.5 mL·kg(-1)·min(-1) and 6 beats·min(-1) per decade. The highest oxygen pulses were observed in the 3 youngest age groups (20-29 years, 30-39 years, 40-49 years) among men and women; 22.3 mL·beat(-1)±3.6 and 14.7 mL·beat(-1)±2.7 (sex differences, p<0.001), respectively, with no significant difference between these age groups. After the age of 50 we observed an 8% reduction per decade among both sexes. Borg scores appear to give a good estimate of the relative exercise intensity, although observing a slightly different relationship than reported in previous reference material from small populations. CONCLUSION: This is the largest European reference material of objectively measured parameters of aerobic fitness and exercise-physiology in healthy men and women aged 20-90 years, forming the basis for an easily accessible, valid and understandable tool for improved training prescription in healthy men and women.

A Multi-Center Comparison of O2peak Trainability Between Interval Training and Moderate Intensity Continuous Training

Camilla J. Williams, Brendon J. Gurd, Jacob T. Bonafiglia +27 more · Frontiers in Physiology · 2019 · 111 citations

There is heterogeneity in the observed V̇O2peak response to similar exercise training, and different exercise approaches produce variable degrees of exercise response (trainability). The aim of this study was to combine data from different laboratories to compare V̇O2peak trainability between various volumes of interval training and Moderate Intensity Continuous Training (MICT). For interval training, volumes were classified by the duration of total interval time. High-volume High Intensity Interval Training (HIIT) included studies that had participants complete more than 15 minutes of high intensity efforts per session. Low-volume HIIT/Sprint Interval Training (SIT) included studies using less than 15 minutes of high intensity efforts per session. In total, 677 participants across 18 aerobic exercise training interventions from 8 different universities in 5 countries were included in the analysis. Participants had completed 3 weeks or more of either high-volume HIIT (n=299), low-volume HIIT/SIT (n=116), or MICT (n=262) and were predominately men (n=495) with a mix of healthy, elderly and clinical populations. Each training intervention improved mean V̇O2peak at the group level (p<0.001). After adjusting for covariates, high-volume HIIT had a significantly greater (P<0.05) absolute V̇O2peak increase (0.29 L/min) compared to MICT (0.20 L/min) and low-volume HIIT/SIT (0.18 L/min). Adjusted relative V̇O2peak increase was also significantly greater (P<0.01) in high-volume HIIT (3.3 ml/kg/min) than MICT (2.4 ml/kg/min) and insignificantly greater (P=0.09) than low-volume HIIT/SIT (2.5 mL/kg/min). Based on a high threshold for a likely response (technical error of measurement plus the minimal clinically important difference), high-volume HIIT had significantly more (P<0.01) likely responders (31%) compared to low-volume HIIT/SIT (16%) and MICT (21%). Covariates such as age, sex, the individual study, population group, sessions per week, study duration and the average between pre and post V̇O2peak explained only 17.3% of the variance in V̇O2peak trainability. In conclusion, high-volume HIIT had more likely responders to improvements in V̇O2peak compared to low-volume HIIT/SIT and MICT.

Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training

Thomas Stöggl, Billy Sperlich · Frontiers in Physiology · 2014 · 275 citations

UNLABELLED: ENDURANCE ATHLETES INTEGRATE FOUR CONDITIONING CONCEPTS IN THEIR TRAINING PROGRAMS: high-volume training (HVT), "threshold-training" (THR), high-intensity interval training (HIIT) and a combination of these aforementioned concepts known as polarized training (POL). The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. METHODS: Forty eight runners, cyclists, triathletes, and cross-country skiers (peak oxygen uptake: (VO2peak): 62.6 ± 7.1 mL·min(-1)·kg(-1)) were randomly assigned to one of four groups performing over 9 weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. RESULTS: POL demonstrated the greatest increase in VO2peak (+6.8 ml·min·kg(-1) or 11.7%, P < 0.001), time to exhaustion during the ramp protocol (+17.4%, P < 0.001) and peak velocity/power (+5.1%, P < 0.01). Velocity/power at 4 mmol·L(-1) increased after POL (+8.1%, P < 0.01) and HIIT (+5.6%, P < 0.05). No differences in pre- to post-changes of work economy were found between the groups. Body mass was reduced by 3.7% (P < 0.001) following HIIT, with no changes in the other groups. With the exception of slight improvements in work economy in THR, both HVT and THR had no further effects on measured variables of endurance performance (P > 0.05). CONCLUSION: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables.

High-Intensity Interval Training Increases Cardiac Output and V˙O2max

Todd A. Astorino, Ross M. Edmunds, Amy S. Clark +5 more · Medicine & Science in Sports & Exercise · 2016 · 150 citations

Increases in maximal oxygen uptake (V˙O2max) frequently occur with high-intensity interval training (HIIT), yet the specific adaptation explaining this result remains elusive. PURPOSE: This study examined changes in V˙O2max and cardiac output (CO) in response to periodized HIIT. METHODS: Thirty-nine active men and women (mean age and V˙O2max = 22.9 ± 5.4 yr and 39.6 ± 5.6 mL·kg·min) performed HIIT and 32 men and women (age and V˙O2max = 25.7 ± 4.5 yr and 40.7 ± 5.2 mL·kg·min) were nonexercising controls (CON). The first 10 sessions of HIIT required eight to ten 60 s bouts of cycling at 90%-110% percent peak power output interspersed with 75 s recovery, followed by randomization to one of three regimes (sprint interval training (SIT), high-volume interval training (HIITHI), or periodized interval training (PER) for the subsequent 10 sessions. Before, midway, and at the end of training, progressive cycling to exhaustion was completed during which V˙O2max and maximal CO were estimated. RESULTS: Compared with CON, significant (P < 0.001) increases in V˙O2max in HIIT + SIT (39.8 ± 7.3 mL·kg·min to 43.6 ± 6.1 mL·kg·min), HIIT + HIITHI (41.1 ± 4.9 mL·kg·min to 44.6 ± 7.0 mL·kg·min), and HIIT + PER (39.5 ± 5.6 mL·kg·min to 44.1 ± 5.4 mL·kg·min) occurred which were mediated by significant increases in maximal CO (20.0 ± 3.1 L·min to 21.7 ± 3.2 L·min, P = 0.04). Maximal stroke volume was increased with HIIT (P = 0.04), although there was no change in maximal HR (P = 0.88) or arteriovenous O2 difference (P = 0.36). These CO data are accurate and represent the mean changes from pre- to post-HIIT across all three training groups. CONCLUSIONS: Increases in V˙O2max exhibited in response to different HIIT regimes are due to improvements in oxygen delivery.

Greater effects of high- compared with moderate-intensity interval training on cardio-metabolic variables, blood leptin concentration and ratings of perceived exertion in obese adolescent females

Ghazi Racil, Jérémy Coquart, Wassim Elmontassar +5 more · Biology of Sport · 2016 · 143 citations

This study examined the effects of high- vs. moderate-intensity interval training on cardiovascular fitness, leptin levels and ratings of perceived exertion (RPE) in obese female adolescents. Forty-seven participants were randomly assigned to one of three groups receiving either a 1:1 ratio of 15 s of effort comprising moderate-intensity interval training (MIIT at 80% maximal aerobic speed: MAS) or high-intensity interval training (HIIT at 100% MAS), with matched 15 s recovery at 50% MAS, thrice weekly, or a no-training control group. The HIIT and MIIT groups showed improved (p < 0.05) body mass (BM), BMI Z-score, and percentage of body fat (%BF). Only the HIIT group showed decreased waist circumference (WC) (p = 0.017). The effect of exercise on maximal oxygen uptake (VO2max) was significant (p = 0.019, ES = 0.48 and p = 0.010, ES = 0.57, HIIT and MIIT, respectively). The decrease of rate-pressure product (RPP) (p < 0.05, ES = 0.53 and ES = 0.46, HIIT and MIIT, respectively) followed the positive changes in resting heart rate and blood pressures. Blood glucose, insulin level and the homeostasis model assessment index for insulin decreased (p < 0.05) in both training groups. Significant decreases occurred in blood leptin (p = 0.021, ES = 0.67 and p = 0.011, ES = 0.73) and in RPE (p = 0.001, ES = 0.76 and p = 0.017, ES = 0.57) in HIIT and MIIT, respectively. In the post-intervention period, blood leptin was strongly associated with %BF (p < 0.001) and VO2max (p < 0.01) in the HIIT and MIIT groups, respectively, while RPE was strongly associated with BM (p < 0.01) in the HIIT group. The results suggest that high-intensity interval training may produce more positive effects on health determinants in comparison with the same training mode at a moderate intensity.

Exercise efficiency relates with mitochondrial content and function in older adults

Nicholas T. Broskey, Andreas Boss, Elie-Jacques Fares +7 more · Physiological Reports · 2015 · 51 citations

Chronic aerobic exercise has been shown to increase exercise efficiency, thus allowing less energy expenditure for a similar amount of work. The extent to which skeletal muscle mitochondria play a role in this is not fully understood, particularly in an elderly population. The purpose of this study was to determine the relationship of exercise efficiency with mitochondrial content and function. We hypothesized that the greater the mitochondrial content and/or function, the greater would be the efficiencies. Thirty-eight sedentary (S, n = 23, 10F/13M) or athletic (A, n = 15, 6F/9M) older adults (66.8 ± 0.8 years) participated in this cross sectional study. V˙O2peak was measured with a cycle ergometer graded exercise protocol (GXT). Gross efficiency (GE, %) and net efficiency (NE, %) were estimated during a 1-h submaximal test (55% V˙O2peak). Delta efficiency (DE, %) was calculated from the GXT. Mitochondrial function was measured as ATPmax (mmol/L/s) during a PCr recovery protocol with (31)P-MR spectroscopy. Muscle biopsies were acquired for determination of mitochondrial volume density (MitoVd, %). Efficiencies were 17% (GE), 14% (NE), and 16% (DE) higher in A than S. MitoVD was 29% higher in A and ATPmax was 24% higher in A than in S. All efficiencies positively correlated with both ATPmax and MitoVd. Chronically trained older individuals had greater mitochondrial content and function, as well as greater exercise efficiencies. GE, NE, and DE were related to both mitochondrial content and function. This suggests a possible role of mitochondria in improving exercise efficiency in elderly athletic populations and allowing conservation of energy at moderate workloads.

Real-time feedback by wearables in running: Current approaches, challenges and suggestions for improvements

Bas Van Hooren, Jos Goudsmit, Juan Restrepo +1 more · Journal of Sports Sciences · 2019 · 135 citations

Injuries and lack of motivation are common reasons for discontinuation of running. Real-time feedback from wearables can reduce discontinuation by reducing injury risk and improving performance and motivation. There are however several limitations and challenges with current real-time feedback approaches. We discuss these limitations and challenges and provide a framework to optimise real-time feedback for reducing injury risk and improving performance and motivation. We first discuss the reasons why individuals run and propose that feedback targeted to these reasons can improve motivation and compliance. Secondly, we review the association of running technique and running workload with injuries and performance and we elaborate how real-time feedback on running technique and workload can be applied to reduce injury risk and improve performance and motivation. We also review different feedback modalities and motor learning feedback strategies and their application to real-time feedback. Briefly, the most effective feedback modality and frequency differ between variables and individuals, but a combination of modalities and mixture of real-time and delayed feedback is most effective. Moreover, feedback promoting perceived competence, autonomy and an external focus can improve motivation, learning and performance. Although the focus is on wearables, the challenges and practical applications are also relevant for laboratory-based gait retraining.