Showing papers by "Roy J. Shephard published in 2016"

The objective monitoring of physical activity : contributions of accelerometry to epidemiology, exercise science and rehabilitation

Abstract: Introduction: a new perspective on the epidemiology of physical activity.- Chapter 1. Physical activity and optimal health: the challenge to epidemiology.- Chapter 2. History of physical activity measurement in epidemiology.- Chapter 3. Evolution of the pedometer.- Chapter 4. Newer approaches to the objective measurement of physical activity.- Chapter 5. Optimal patterns for the sampling of physical activity in various age groups and environments.- Chapter 6. New information on population activity patterns revealed by objective monitoring.- Chapter 7. Can the epidemiologist learn more from sedentary behaviour than from the measurement of physical activity?.- Chapter 8. New perspectives on activity/disease relationships yielded by objective monitoring.- Chapter 9. Excessive appetite vs. inadequate physical activity in the pathology of obesity. Evidence from objective monitoring.- Chapter 10. Objective monitoring and the challenge of defining dose/response relationships for the prevention of chronic disease.- Chapter 11. The economic benefits of increased physical activity as seen through an objective lens.- Chapter 12. Limitations of current objective monitors and the potential to overcome these problems.- Chapter 13. Future directions and conclusions.

The 2016 Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) and electronic Physical Activity Readiness Medical Examination (ePARmed-X+).

Abstract: This article contains the current CONSENSUS PANEL APPROVED AND OFFICIAL version of the Physical Activity Readiness Questionnaire for Everyone (PAR-Q+). The new PAR-Q+ and ePARmed-X+ were introduced officially at the 3rd International Congress on Physical Activity and Public Health in Toronto, Ontario, Canada (May 5-8, 2010) by Drs. Darren Warburton, Norman Gledhill, Veronica Jamnik, and Shannon Bredin. The first peer reviewed article containing the PAR-Q+ was published in the Health & Fitness Journal of Canada and subsequent updates have been made through this journal. Owing to the evidence-based nature of the PAR-Q+ and ePARmed-X+ both forms require routine update as the evidence expands. These ongoing revisions are made by the PAR-Q+ Collaboration and evaluated by an international consensus committee. This article contains the 2016 PAR-Q+ that includes significant changes from our original version. This version replaces all previous versions. This is the current evidence-based and consensus panel approved version of the PAR-Q+.

Responses of the human spleen to exercise

Abstract: The human spleen shows a decrease in volume of around 40% early during vigorous exercise and in response to other stressful stimuli such as maximal apnoea and the breathing of hypoxic gas mixtures Contraction seems an active response, mediated by alpha-adrenergic fibres in the splenic nerve Given the relatively small size of the human spleen, the effect upon physical performance is likely to be small; the augmentation of total blood volume is <2%, and even taking account of other causes of haemoconcentration during vigorous exercise, the increase of haematocrit is <10% However, one of two studies suggested that the haemoconcentration may be sufficient to cause errors in the traditional method for calculating exercise-induced changes of plasma volume The spleen also contributes leucocytes and platelets to the general circulation as part of the "fight or flight" reaction to stressors The mobilisation of leucocytes proceeds more slowly than that of the red cells; it depends not only upon an active contraction of the spleen, but also a modulation of leucocyte adhesion molecules Splenectomy impairs exercise performance in horses, but human performance data are lacking; overall health effects seem minimal, and many patients live many years after removal of their spleens

The Case for Increased Physical Activity in Chronic Inflammatory Bowel Disease: A Brief Review

Abstract: Regular physical activity reduces the risk of colon cancer, but there is little information on the merits of such activity in the prevention and management of chronic inflammatory bowel disease (CIBD). The present systematic review thus documents current levels of habitual physical activity and aerobic and muscular function in CIBD, and examines the safety, practicality and efficacy of exercise programmes in countering the disease process, correcting functional deficits and enhancing quality of life. A systematic search of the Ovid/Medline database from January 1996 to May 2015 linked the terms physical activity/motor activity/physical fitness/physical training/physical education/training/exercise/exercise therapy with Crohn's disease/colitis/ulcerative colitis/inflammatory bowel disease, supplementing this information by a scanning of reference lists and personal files.12 of 16 published studies show a low level of habitual physical activity in CIBD, with sub-normal values for aerobic power, lean tissue mass and muscular strength. 3 of 4 studies suggest physical activity may reduce the risk of developing IBD, and 11 interventions all note that exercise programmes are well tolerated with some decreases of disease activity, and functional gains leading to an increased health-related quality of life. Moreover, programme compliance rates compare favourably with those seen in the treatment of other chronic conditions. More information on mechanisms is needed, but regular moderate aerobic and/or resistance exercise improves the health status of patients with CIBD both by modulating immune function and by improving physical function. A regular exercise programme should thus become an important component in the management of CIBD.

Exercise proteinuria and hematuria: current knowledge and future directions.

Abstract: Introduction Transient proteinuria and hematuria are apparently benign sequelae of intensive physical activity. However, there is a need to establish underlying causes and reasons for progression to chronic renal damage, as well as effects of training in healthy individuals and in those with microalbuminuria. Evidence acquisition The Ovid/Health Star database was searched from 1994 to November 2014. Terms for the kidneys (adverse effects, blood supply, epidemiology, injuries, pathology, physiology and secretion) and proteinuria (classification, complications, epidemiology, etiology, mortality, physiopathology, prevention and control) with terms related to physical activity (physical activity/motor activity, exercise/exercise therapy, fitness/physical fitness, physical education/physical education and training, and rehabilitation). Evidence synthesis Review of 519 abstracts yielded 194 relevant hits, supplemented by 70 items from other sources. This material related to both healthy adults (125 items) and renal disease (139 items). The prevalence (18-100%) and duration (1-6 days) of exercise proteinuria varied widely, with risks affected by exercise intensity, posture, age, heat load, altitude and disease. Moderate training reduced exercise proteinuria in healthy individuals and in chronic renal disease. Factors contributing to exercise proteinuria may include vascular changes, hypoxia, lactate accumulation, oxidant stress, hormonal changes and sepsis. Exercise hematuria is frequent; some potential causes are similar to those for proteinuria, but foot-strike and bladder trauma are probably more important. Progression to permanent renal damage is rare. Conclusions Exercise proteinuria and hematuria are generally transient. However, there remains a need to clarify causation and factors leading to permanent renal damage.

Effects of recreational soccer on physical fitness and health indices in sedentary healthy and unhealthy subjects.

Abstract: Recreational soccer (RS) is becoming a popular alternative to the classical continuous exercise mode used for the improvement of cardiovascular and metabolic fitness in untrained people. The objective of this paper was to conduct a detailed systematic review of the literature, identifying the physiological responses to RS and the training effects of RS on aerobic fitness and health in untrained healthy individuals and clinical patients. PubMed, Google Scholar and ScienceDirect databases were searched using terms related to recreational soccer. Inclusion criteria were randomized controlled trials (RCT) that assessed acute physiological responses to RS or the training effects of RS on physical fitness and health in sedentary, untrained subjects of any age or health status. All studies were assessed for methodological quality using the PEDro scale. Thirty-five articles met the inclusion criteria; seven examined the acute response to RS, and 28 assessed training effects. Clear evidence was found that RS had positive effects on many health-related indices and variables, including VO2max (gains of 7-16%), blood pressure (reductions of 6-13 mmHg), body composition (decreased fat mass and improved indices of bone health), and metabolic and cardiac function. These positive effects were observed in both healthy individuals and clinical patients, irrespective of age or sex. Although this review provides clear evidence of the positive effects of RS on health, most studies had limitations of methodology (an average PEDro score < 6). Furthermore, many of the training studies were from a small number of research groups. Future studies should be extended to other countries and institutions to ensure generality of the results. Regular RS training leads to significant cardiovascular and muscular adaptations and gains of health both in sedentary individuals and clinical patients at all ages, suggesting that RS is a potentially highly motivational method to enhance population health.

Consensus on Evidence-Based Preparticipation Screening and Risk Stratification

Abstract: This chapter is designed to provide a summary of the current consensus on evidence-based, best practice guidelines for safe and effective preparticipation screening and risk stratification. We summarize briefly the irrefutable body of evidence supporting the health benefits of routine physical activity/exercise (particularly in the elderly and at-risk populations). We also highlight the benefitto-risk paradox, wherein routine physical activity decreases the long-term risk for premature mortality and at least 25 chronic medical conditions, while acute bouts of activity (particularly vigorous-intensity exercise) increase transiently the risk for adverse potentially life-threatening events (such as sudden cardiac death). We examine the various risk factors associated with the transient risks after exercise testing or training, identifying how low the risks are and how regular physical activity participation reduces these transient risks. We highlight current advances in preparticipation-screening and risk stratification strategies and the implications for the elderly (including those living with chronic medical conditions). These advances have resulted in very few participants being sent to see a physician prior to participating in a physical activity program. As such, innovations in preparticipation screening and risk stratification have significantly reduced the barriers for physical activity participation so that the vast majority of society can reap the health benefits of routine physical activity.

Effects of in-season short-term aerobic and high-intensity interval training program on repeated sprint ability and jump performance in handball players.

Abstract: Background This study examined the effects of a 7-week in-season aerobic and high-intensity interval-training program on performance tests linked to successful handball play (e.g., repeated sprint and jumping ability). Methods Thirty participants (age 17.0±1.2 years, body mass 81.1±3.4 kg, height 1.82±0.07 m) performed a Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), a squat (SJ) and a Countermovement Jump Test (CMJ), as well as a repeated Sprint Ability Test (RSA). From this, maximal aerobic speed (MAS, reached at the end of the Yo-Yo IR1), jumping ability, best time in a single sprint trial (RSAbest), total time (RSATT) and the performance decrement (RSAdec) during all sprints were calculated. Later, subjects were randomly assigned to a control group (CG; N.=15) performing their normal training schedule (5 weekly sessions of ~90 minutes of handball training) or an experimental group (EG; N.=15). The EG performed two 30 min sessions per week of high-intensity aerobic exercises at 100-130% of MAS in addition to their normal training schedule. Results A significant improvement in MAS (d=4.1), RSAbest (d=1.9), RSATT (d=1.5) and RSAdec (d=2.3) after the training period was demonstrated. Also, significant interaction effects (time x group) were found for all parameters as the EG significantly improved performances in all tests after training. The greatest interaction effects were observed in MAS (η2=0.811) and CMJ (η2=0.759). No relevant changes in test performances were found in the CG (mean d=-0.02). Conclusions These results indicate that individually speed-controlled aerobic and interval training is effective for improving specific handball performance.

Rapid weight loss in the context of Ramadan observance: Recommendations for judokas

Abstract: Judo is a weight-classified combat sport, and many athletes seek to compete at the lightest possible weight category to gain an advantage from competing against shorter/smaller, and supposedly weaker opponents. To achieve a desired weight, most judokas opt for rapid weight loss techniques. Short-duration maximal efforts are not greatly affected by "making weight", but prolonged and/or repeated exercise is significantly impaired. Negative effects on mood, ratings of perceived exertion, and cognitive function are also reported. Moreover, rapid weight loss reduces maximal cardiac output and glycogen stores, and impairs thermo-regulation. Limited empirical data suggest that Ramadan reduces judokas' performance, and this is likely to be exacerbated by attempts at rapid weight loss. Weight reduction during Ramadan tends to be counterproductive, and judokas who aim for a lower weight category are advised to attempt any desired reduction of body mass during the weeks leading up to Ramadan, rather than during the holy month.

Effects of Ramadan observance on repeated cycle ergometer sprinting and associated inflammatory and oxidative stress responses in trained young men

Abstract: Introduction: was to assess the effects of Ramadan observance upon repeated sprints and associated inflammatory and oxidative stress responses. Methods: Ten young trained boxers were tested during a control period (C), at the end of the first week (R-1), and during the fourth week of Ramadan observance (R-4). On each occasion, they performed three vertical jumps, 10 x 6 s repeated sprints on a cycle ergometer, followed by three final vertical jumps 1 min after. Surface electrodes measured the EMG activity of the vastus lateralis during jumps performed before and after sprinting. Oxidative stress (malondialdehyde, total antioxidant and catalase), inflammatory markers (C-reactive protein, Interleukin-6 and homocysteine), muscle damage (CPK and LDH) and blood glucose were measured at rest and after completing the exercise protocol. Results: The overall sprint performance was reduced at R-1 compared to C (-6.3 ± 1.2%, p = 0.025), but had recovered by R-4. Jump height decreased after the repeated sprints (p<0.01), without significant changes in EMG parameters. Oxidative stress indices, inflammatory markers, and muscle damage measured after the protocol exercise were unaffected during fasting. Conclusion: The correction of sprint performance may highlight some adaptive responses to fasting. The unchanged of the selected fatigue biomarkers after the repeated sprint protocol suggest that the dietary restriction related to Ramadan is not severe enough to induce significant changes in the metabolism of our trained athletes.

Sickle cell trait: what are the costs and benefits of screening?

Abstract: Introduction Eight percent of African Americans are carriers of the sickle cell trait. Some regard this as a benign anomaly, but others point to incidents of sudden exercise-related death, calling for a preliminary screening of either all athletes or those of African-American ancestry. This brief review considers the costs and benefits of such screening. Evidence acquisition The Ovid/Health Star data-base was searched from 1996 to June 2015. 2014. The terms "exercise", "exercise therapy", "sports", "athletes", "physical activity/motor activity" and "physical fitness" were combined to yield 227,120 citations. Likewise, the terms "sickle cell trait", "sickle cell disease", "splenic infarction", "hemoglobin S" and "rhabdomyolysis" identified 12,325 citations. A combination of the 2 searches yielded 416 abstracts. Evidence synthesis Excluding items relating to animal research or forms of rhabdomyolysis other than sickling left 375 abstracts; 115 papers merited full examination. This material covered the risks of sickle cell trait and of screening (55 items), effects upon physical performance (31 items), cellular mechanisms (23 items), nutrition (4 items), and other topics (2 items). Supplemented material was drawn from reference lists and personal files. The tendency to sickling was provoked by excessive exercise relative to physical condition in hot or hypoxic conditions, and by local tissue acidosis, conditions that were best avoided by all athletes. The condition had little impact upon physical performance, but the relative risks of heat illness, exertional rhabdomyolysis, splenic infarction and sudden death were all increased by the sickle cell trait. The absolute number of critical incidents was nevertheless small, calling for close assessment of the costs and putative benefits of widespread screening. Conclusions Sports physicians should be aware of the clinical picture of sickling and be prepared to treat it. Screening may be cost-effective if targeted to black athletes involved in certain sports, although it has yet to be demonstrated how far the diagnosis of sickle cell trait reduces the risk of death when exercising in an adverse environment. A better tactic may be to reduce risks for all competitors by educating athletes and their coaches to adopt an intensity of training appropriate to the individual's physical condition, to maintain full hydration, and to avoid exposure to excessive heat and hypoxia.

The Economic Benefits of Increased Physical Activity as Seen Through an Objective Lens

Abstract: Over a lifetime, the annual per capita direct and indirect costs associated with cardiovascular disease amount to around 1 year’s salary for the average wage-earner. Additional costs arise from other forms of chronic disease where physical activity could potentially play a preventive role. Questionnaires and other methods of categorizing an individual’s habitual physical activity suggest that per capita health-care costs may be half as great in those members of the community who are classed as physically active, and some authors have thus argued that overall costs could be halved if everyone were to become active. Objective monitoring is now offering the potential for a more precise gradation of the costs attributable to individual diseases in relation to levels of habitual physical activity. Rather than assuming a generic beneficial effect of “activity,” it has become possible to quantitate the magnitude of the economic benefits likely from the small increases of activity that can be achieved in sedentary populations with respect to each of a range of chronic diseases. The application of objective monitoring demonstrates that the greatest economic benefit is likely from changing the behaviour of the most sedentary individuals in a given population. It also identifies specific clinical conditions where an increase of habitual physical activity should yield large financial dividends. If applied on a large scale, objective monitoring offers the potential for prospective monitoring of the effects of defined increases in exercise behaviour upon immediate charges to the health care system, as well as an objective assessment of the costs of motivating defined changes in physical activity patterns. To date, objective monitors have only been applied to two economic analyses in elderly people (where the primary activity of walking is readily monitored, but also where a substantial fraction of population health care costs are incurred). Extension of these analyses to younger adults is desirable, but it will require the development of a second generation of objective monitors that can respond accurately to the full range of sports and pastimes pursued by the younger generation.

The endurance athlete's "stitch": Etiology and management of exercise-related transient abdominal pain

Abstract: Background: The endurance athlete's "stitch," or exercise-related transient abdominal pain (ETAP), all too commonly limits the performance of endurance athletes, but its origin, management and possible methods of prevention remain unclear. Methods: Published research was reviewed systematically from January 1996 through May 2015.The terms "Athletic Stitch," "Pain in the side" OR "Abdominal pain" were paired with "Exercise/Exercise therapy," "Physical education/Training," OR Fitness/Physical fitness" to identify a total of 66 papers. 35 of these articles relevant to review objectives were supplemented by an additional 50 citations drawn from reference lists and personal files. Results : About a fifth of participants in aerobic endurance events are affected by ETAP on any one occasion, and perhaps two thirds of competitors experience ETAP at least once during a year. The risk seems greater in younger, less experienced and female athletes. Postulated causes that include visceral ischaemia, visceral vibration, ischaemia and/or spasm of the respiratory muscles, postural disorders, peritoneal irritation, and psychological factors.Treatment currently remains empirical. Optimizing physical condition, strengthening abdominal and spinal muscles, and avoiding food and hypertonic fluids immediately before an event appear to reduce the risks of ETAP. A slowing of pace, bending, local pressure and an abdominal binder may give immediate relief; the merits of spinal manipulation have yet to be confirmed Conclusions : Empirical remedies as yet have limited efficacy, and it remains necessary to develop a clear unifying hypothesis of etiology before evidence-based recommendations for the prevention and treatment of ETAP. Although ETAP may impair performance, it does not have any serious sequelae; the important objective for the practitioner is to distinguish it from other more dangerous causes of abdominal pain.

A History of Physical Activity Measurement in Epidemiology

Abstract: Although Hippocrates is often considered the father of epidemiology, John Snow also played an important role with his studies of cholera epidemics in Victorian London. A detailed study of relationships between physical activity and the prevention of chronic disease did not begin until the mid-twentieth century, with Jeremy Morris in London, and Henry Taylor and Ralph Paffenbarger in the U.S. leading investigations of the epidemic of ischaemic heart disease. Occupation or athletic status was initially used to classify the habitual physical activity of study participants, but as daily energy expenditures diminished at most work sites, interest shifted to questionnaire and diary assessments of leisure activity. Other options to classify the habitual activity of subjects included occasional quasi-experimental assignments to exercise programmes, determinations of aerobic fitness, and a study of “natural experiments” where community activity patterns were known to have diminished. Such initiatives generally distinguished active from inactive individuals, but attempts to determine the intensity and volume of exercise that was undertaken often yielded unrealistically large values. The introduction of modern pedometer/accelerometers at first seemed to promise accurate, objective assessments of habitual activity. Although quite successful in assessing standardized activities such as steady walking, the newer monitors have shown much less consistency in measuring the wide range of activities encountered in normal daily living. Future research may focus upon some combination of activity monitoring with global position-sensing and posture detecting devices.

Physical Activity and Optimal Health: The Challenge to Epidemiology

Abstract: Epidemiologists seek associations between environmental factors, lifestyle influences and human health; they use current modifications of a series of guidelines enunciated by Bradford Hill to assess the hypothesis that observed associations are causal in nature. We now have a long list of medical conditions where physical activity has been suggested as having a beneficial influence in prevention and/or treatment. Questionnaire evaluations of such claims have been hampered by the limited reliability and validity of self-reports. The introduction of pedometer/accelerometers and other objective monitors has facilitated the determination of causality, allowing investigators to study the effects of clearly specified types, intensities, frequencies and durations of physical activity. Nevertheless, further improvement of monitoring devices is needed in order that epidemiologists can capture the full range of activities typical of children and younger adults. Objective monitoring does not support the hypothesis that a minimum intensity of physical effort is needed for health benefit; indeed, in sedentary individuals the largest improvements in health are often seen with quite small increases of habitual activity. There is no obvious threshold of response, but for many medical conditions available data suggests a ceiling of benefit, with no apparent gains of health once habitual activity attains a specified upper limit. Causality can never be totally proven, but objective data allows the inference that multiple health benefits will stem from moderate daily physical activity; the evidence is sufficiently strong that people of all ages should be urged to adopt such behaviour.

Excessive Appetite vs. Inadequate Physical Activity in the Pathology of Obesity: Evidence from Objective Monitoring

Abstract: Objective monitoring of physical activity confirms the impression formed from questionnaire responses that both adults and children who are overweight or obese take less physical activity than their peers who have a healthy body mass. Pedometer/accelerometer data provides relatively precise information on the magnitude of the deficit in physical activity, which amounts to around 2000 steps/day, or 15–20 minutes/day of moderate and/or vigorous physical activity. In some studies of those who are grossly obese, there is also evidence of an increase in sedentary time. The overall difference in daily energy expenditure between those of normal weight and those who are overweight or obese is quite small, underlining that the build-up of fat usually occurs over several years. Pedometers and accelerometers provide a useful initial stimulus to greater physical activity, although there remains a need to examine how to maximize the impact of instrumentation and to sustain its motivational effect. There is now good evidence that for at least a few months, the physical activity of an obese adult can be augmented by 2000–3000 steps/day, and that this initiates a slow but consistent loss of body fat (0.05–0.1 kg/week). Relative to dieting, the increase of physical activity also brings other health advantages, including increases of aerobic power and lean tissue, and a decrease of metabolic and cardiac risk factors.

New Perspectives on Activity/Disease Relationships Yielded by Objective Monitoring

Abstract: The Hockley Valley Consensus Symposium based most of its conclusions on dose/response relationships between physical activity and disease on subjective questionnaire reports. In this chapter, we summarize the findings from the Hockley Valley meeting, and we examine how far these conclusions have been amplified and/or modified by the use of objective physical activity monitors. Among a wide range of topics, we have included data on objective activity monitoring in relation to all-cause mortality, cardiac death, cardiovascular disease, stroke, peripheral vascular disease, hypertension, cardiac and metabolic risk factors, diabetes mellitus, obesity, low back pain. osteoarthritis, osteoporosis, chronic chest disease, cancer, depression, quality of life and the capacity for independent living. The introduction of objective monitoring has clarified dose/response relationships in a number of areas, allowing us to define relationships in terms of objective metrics (the number of steps taken per day). However, much of the information that is currently available remains cross-sectional in type. In many areas of rehabilitation, the pedometer/accelerometer seems a useful motivating device, providing well-documented increments of weekly activity. However, there remains a need for well-designed longitudinal trials, using objective monitors to follow changes in habitual activity and thus to demonstrate causality in the association between physical activity and good health.

Objective Monitoring and the Challenge of Defining Dose/Response Relationships for the Prevention of Chronic Disease

Abstract: The form of the dose/response relationship linking habitual physical activity to major health outcomes is of practical importance for those who are formulating public health recommendations on minimum daily physical activity needs. However, available information on the form of this relationship is conflicting. One might anticipate that the optimal physical activity pattern would mimic that of our hunter-gatherer ancestors. Data gathered on traditional Inuit hunters point to a large daily energy expenditure in many types of hunting; this is accumulated mainly through long days of moderate physical activity. Studies based upon occupational classifications also suggest health benefit from vigorous physical exercise at work, and this view is supported by early questionnaire analyses of leisure behaviour. However, a systematic survey of questionnaire-based reports revealed no clear picture, because of differing methods of measuring and classifying physical activity, substantial inaccuracies in self-reports, and examination of a wide variety of health outcomes. Other studies, using simple measures of fitness as surrogate indicators of accumulated physical activity, have pointed to the largest health benefits being gained from a moderate increment of fitness. Objective physical activity monitors allow a much finer gradation of physical activity patterns, and thus have the potential to clarify dose/response relationships. However, this potential has not as yet been realized. The samples tested have been small, and the health outcomes examined have been physiological changes rather than clinical events. Confidence intervals for the benefits realized at different levels of physical activity have thus been as large or larger than those found in questionnaire studies. Future developments should permit the use of objective monitors on a much larger scale; a 100-fold increase in subject numbers seems likely to overcome current problems.

Regulating exercise intensity when heart-rate based prescription is compromised

Abstract: Background: Clinical conditions such as beta-blockade, cardiac conduction defects, use of a cardiac pacemaker, and cardiac transplantation preclude use of heart rate to regulate the intensity of prescribed exercise. Purpose: To evaluate the suggestion that Borg's RPE may provide a valid alternative, and to weigh possible alternatives. Methods: A brief review of factors modifying RPE, and an analysis of RPE data obtained in patients following cardiac transplantation. Results: Many factors modify an individual's perceptions of effort, and in consequence simply exercising to a fixed RPE can result in either too low an intensity to induce the required training, or a dangerously high intensity of exercise. Conclusions: RPE does not provide a safe method of regulating exercise after cardiac transplantation. A better alternative is to establish the individual's oxygen cost of walking, and to prescribe a set walking distance to be covered in a set time, reserving the RPE for a fine-tuning of this prescription