We sought to clarify the significance of cardiac dysfunction and to assess its relationship with elevated biomarkers by using cardiovascular magnetic resonance imaging in healthy, middle-aged subjects immediately after they ran 26.2 miles. Cardiac dysfunction and elevated blood markers of myocardial injury have been reported after prolonged strenuous exercise. From 425 volunteers, 13 women and 12 men were randomly selected, provided medical and training history, and underwent baseline cardiopulmonary exercise testing to exhaustion. Blood biomarkers, cardiovascular magnetic resonance imaging, and 24-h ambulatory electrocardiography were performed 4 wk before and immediately after the race. Participants were 38.7+/-9.0 yr old, had baseline peak oxygen consumption of 52.9+/-5.6 ml.kg(-1).min(-1), and completed the marathon in 256.2+/-43.5 min. Cardiac troponin I and B-type natriuretic peptide increased following the race (P=0.001 and P<0.0001, respectively). Cardiovascular magnetic resonance-determined pre- and postmarathon left ventricular ejection fractions were comparable, 57.7+/-4.1% and 58.7+/-4.3%, respectively (P=0.32). Right atrial volume index increased from 46.7+/-14.4 to 57.0+/-14.5 ml/m2 (P<0.0001). Similarly, right ventricular end-systolic volume index increased from 47.4+/-11.2 to 57.0+/-14.6 ml/m2 (P<0.0001) whereas the right ventricular ejection fraction dropped from 53.6+/-7.1 to 45.5+/-8.5% (P<0.0001). There were no morphological changes observed in the left atrium or ventricle or evidence of ischemic injury to any chamber by late gadolinium enhancement. There were no significant arrhythmias. Marathon running causes dilation of the right atrium and right ventricle, reduction of right ventricular ejection fraction, and release of cardiac troponin I and B-type natriuretic peptide but does not appear to result in ischemic injury to any chamber.

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Background: Sedentary lifestyles and poor physical fitness are major contributors to the current obesity and cardiovascular disease pandemic. Hypothesis: Daily physical activity and cardiorespiratory fitness are correlated in morbidly obese individuals in their free-living environment. Methods: Ten morbidly obese participants continuously wore an activity sensor that measured caloric expenditure, minute-by-minute physical activity, and steps/day over a 72-h period. Following collection of the device data, structured cardiorespiratory fitness testing was performed on each subject. Results: Mean caloric expenditure for all individuals was 2,668±481 kcal/d. On average, subjects took 3,763±2,223 steps. On average 23 h and 51.6 min per d were spent sleeping or engaged in sedentary activity (<3 metabolic equivalents [METs]) and the remaining 8.4 min were spent in moderate activity (3-6 METs). Average peak VO 2 was 16.8±4.7 mL/kg/min. Higher peak VO 2 correlated with higher total caloric expenditure (TCE; r = 0.628, p = 0.05) and trended with higher steps/day (r = 0.591, p = 0.07). Conclusions: Most morbidly obese participants in this study were markedly sedentary. These study results may provide important links between obesity, poor fitness, and cardiovascular disease.

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The use of exercise testing has expanded greatly to help guide decisions about medical management and prognosis in a broad spectrum of patients. Numerous epidemiological studies in people with and without documented coronary artery disease have identified a low level of cardiorespiratory fitness as an independent risk factor for all-cause and cardiovascular mortality and that exercise capacity is inversely associated with healthcare costs. Accordingly, unfit men and women should be counselled to exercise in home-based or group preventative or rehabilitative programmes. In the era of managed care, the use of specialised exercise professionals for the supervision of exercise testing and training may represent a safe and cost-effective alternative to many hospitals, clinics and private physician practices. Clinical exercise physiologists (CEPs) can play a critical role in favourably modifying clients' level of cardiorespiratory fitness and physical activity habits. We detail the training of CEPs and outline the clinical settings where they have contributed substantially to healthcare delivery. We also outline the role of registered clinical exercise physiologists. It is important that exercise prescription is not left to a few individuals or small groups. It needs a concerted programme with all those in a position to make a difference actively contributing.