Acute cardiac effects of marathon running.

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.

Cardiorespiratory fitness and sedentary lifestyle in the morbidly obese.

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 VO2 was 16.8+/-4.7 mL/kg/min. Higher peak VO2 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.

Cardiorespiratory responses to maximal arm and leg exercise in national-class marathon runners.

Marathon runners (MR) are among the most aerobically fit athletes in the world. Although aerobic capacity (VO(2)max) during arm exercise generally varies between 64% and 80% of leg VO(2)max (mean 70%) in healthy men, few data are available regarding the comparative arm fitness of MR. To clarify the relationship between arm and leg fitness in MR, we studied 10 national-class MR (mean + or - standard deviation age 30 + or - 4 years) whose best marathon times averaged < 2 hours and 40 minutes. Each MR underwent lower and upper body maximal exercise evaluations with measurement of cardiorespiratory variables using indirect calorimetry during treadmill testing (standard Bruce protocol) and arm-crank ergometry, respectively. Our subjects achieved VO(2)max levels equaling 75.8 + or - 7.1 mL/kg/min (5.2 + or - 0.6 L/min) during treadmill testing, which was significantly higher than the level of cardiorespiratory fitness achieved during maximal arm exercise (45.4 + or - 12.4 mL/kg/min [3.1 + or - 0.9 L/min]; P < 0.01). In addition, maximal heart rate (183.2 + or - 8.2 vs 163.7 + or - 10 bpm) and systolic blood pressure (201.8 + or - 10.1 vs 186.6 + or - 12.1 mm Hg) were significantly higher (P < 0.01 and P < 0.05, respectively) during maximal leg versus arm exercise. Relative arm fitness (arm VO(2)max/leg VO(2)max) was extremely variable (41%-76%), averaging 60% + or - 13%. Although MR are able to achieve significantly higher VO(2)max values during treadmill testing than those observed in the general population, their relative arm fitness appears to be slightly reduced. These findings add to and strongly support the specificity of measurement and training concept.

Cardiorespiratory fitness and obstructive sleep apnea syndrome in morbidly obese patients.

BACKGROUND: Conflicting data exist regarding the effects of obstructive sleep apnea syndrome (OSAS) on cardiorespiratory fitness in morbidly obese individuals with normal resting left ventricular function. METHODS: Ninety-two morbidly obese subjects without any prior diagnosis of OSAS underwent cardiorespiratory fitness testing, two-dimensional echocardiography, and overnight polysomnography. Using the results of the polysomnogram, comparisons were made between subjects with (n = 42) and without (n = 50) OSAS. RESULTS: Mean body mass index (BMI) for the study population (n = 92) was 48.6 +/- 9.3 kg/m(2) (+/- SD); mean age was 45.5 +/- 9.8 years, and approximately 69% were female. Despite having a higher resting, exercise, and resting mean arterial pressures, the OSAS cohort had a maximum oxygen consumption that was lower than the cohort without OSAS (21.1 mL/kg/min vs 17.6 mL/kg/min; p < 0.001). There was no difference in BMI, age, gender, waist circumference, and neck circumference between those with and without OSAS. Differences were observed between the cohorts in systolic BP, diastolic BP, and heart rate during rest, exercise, and recovery periods. There was no difference in ejection fraction, diastolic dysfunction, and treadmill test duration between cohorts. CONCLUSIONS: Morbidly obese individuals with OSAS demonstrate reduced cardiorespiratory fitness and differing hemodynamic responses to exercise testing as compared with their counterparts without this disorder. These data suggest chronic sympathetic nervous system activation negatively influences aerobic capacity in OSAS.

Peak oxygen consumption and the minute ventilation/carbon dioxide production relation slope in morbidly obese men and women: influence of subject effort and body mass index.

The authors evaluated the minute ventilation/carbon dioxide production relation (VE/VCO2 slope) as a complementary measure to peak oxygen consumption (peak VO2) in 76 patients (mean +/- SD age = 44.3+/-10.8 years, 69.7% female) with morbid obesity (mean +/- SD body mass index [BMI] = 49.4+/-7.0 kg/m(2)), as it is not limited by effort. Nearly one-half (43%) of the patients achieved a peak respiratory exchange ratio <1.10. Mean peak VO2 and VE/VCO2 slope were 17.0+/-3.7 mL/kg/min and 27.8+/-4.0, respectively. Peak VO2 correlated with BMI (r=-0.45, P<.0001), while VE/VCO2 slope did not (r=-0.04, P=.73). There was a linear trend for declining mean peak VO2 (P=.001) but not for VE /VCO2 slope (P=.59) with increasing BMI quintiles. The VE/VCO2 slope is an effort-independent measure that is also independent of BMI and may serve as an adjunctive cardiorespiratory variable when evaluating morbidly obese men and women.

Caloric expenditure in the morbidly obese using dual energy X-ray absorptiometry.

Total caloric expenditure is the sum of resting energy expenditure (REE) and caloric expenditure during physical activity. In this study, we examined total caloric expenditure in 25 morbidly obese patients (body mass index>or=35 kg/m(2)) using dual energy X-ray absorptiometry (DXA) scanning and cardiorespiratory exercise testing. Our results show average REE for all individuals was 2027+/-276 kcal/d and mean net caloric expenditure during 30 min of exercise was 115+/-16 kcals. Assuming the mean of all input values, a strict 1500 kcal/d diet combined with 150 min per wk of structured physical activity, the projected weight change was -7% (8.8+/-6.2 kg) for 6 mo. We conclude that morbidly obese individuals should be able to achieve only a modest weight loss by following minimal national guidelines. These data suggest that more aggressive energy expenditure and caloric restriction targets for long periods of time are needed to result in significant weight loss in this population.

Cardiorespiratory fitness and short-term complications after bariatric surgery.

BACKGROUND: Morbid obesity is associated with reduced functional capacity, multiple comorbidities, and higher overall mortality. The relationship between complications after bariatric surgery and preoperative cardiorespiratory fitness has not been previously studied. METHODS: We evaluated cardiorespiratory fitness in 109 patients with morbid obesity prior to laparoscopic Roux-en-Y gastric bypass surgery. Charts were abstracted using a case report form by reviewers blinded to the cardiorespiratory evaluation results. RESULTS: The mean age (+/- SD) was 46.0 +/- 10.4 years, and 82 patients (75.2%) were female. The mean body mass index (BMI) was 48.7 +/- 7.2 (range, 36.0 to 90.0 kg/m(2)). The composite complication rate, defined as death, unstable angina, myocardial infarction, venous thromboembolism, renal failure, or stroke, occurred in 6 of 37 patients (16.6%) and 2 of 72 patients (2.8%) with peak oxygen consumption (Vo(2)) levels < 15.8 mL/kg/min or > 15.8 mL/kg/min (lowest tertile), respectively (p = 0.02). Hospital lengths of stay and 30-day readmission rates were highest in the lowest tertile of peak Vo(2) (p = 0.005). There were no complications in those with BMI < 45 kg/m(2) or peak Vo(2) > or= 15.8 mL/kg/min. Multivariate analysis adjusting for age and gender found peak Vo(2) was a significant predictor of complications: odds ratio, 1.61 (per unit decrease); 95% confidence interval, 1.19 to 2.18 (p = 0.002). CONCLUSIONS: Reduced cardiorespiratory fitness levels were associated with increased, short-term complications after bariatric surgery. Cardiorespiratory fitness should be optimized prior to bariatric surgery to potentially reduce postoperative complications.

Hemostatic responses to resistance training in patients with coronary artery disease.

PURPOSE: This study was undertaken to evaluate changes in coagulation and fibrinolytic responses to an acute bout of resistance training in patients with coronary artery disease. METHODS: Fourteen low-to-moderate risk men (mean age, 57.6 +/- 9 years; body mass index, 26.7 +/- 4.0 kg/m) with known coronary artery disease participated in this study. All subjects were recruited from the hospital's outpatient cardiac rehabilitation program and none were participating in a resistance training exercise program at the time. Using 8 different resistance training devices, each subject performed 1 set of 10 repetitions to volitional fatigue, resting 1 minute between sets. Blood samples (5 mL) were drawn preexercise, immediate postexercise, and 1 hour postexercise in the seated position. All values were corrected for plasma volume changes. Alterations in von Willebrand Factor antigen, tissue plasminogen activator antigen, and plasminogen activator inhibitor-1 activity were analyzed using repeated measures analysis of variance. RESULTS: Although von Willebrand Factor antigen remained unchanged from preexercise values, tissue plasminogen activator antigen and plasminogen activator inhibitor-1 activity increased and decreased, respectively, in the immediate postexercise recovery period. Moreover, the latter reduction persisted at 1 hour postexercise. CONCLUSION: An acute bout of resistance training improves fibrinolytic potential in men with coronary artery disease, without elevating thrombotic potential. These data support the safety of resistance training in this population when contemporary prescriptive guidelines are used.

Comparative impact of morbid obesity vs heart failure on cardiorespiratory fitness.

BACKGROUND: We are in the midst of an obesity pandemic. Morbid obesity is associated with dyspnea on exertion and higher overall mortality rates. The relations between measures of cardiorespiratory fitness in morbidly obese persons compared to those with heart failure are unknown. METHODS: We compared cardiorespiratory fitness in patients with morbid obesity (n = 43) and established systolic dysfunction heart failure (n = 235), and in age-matched medical control subjects (n = 222) who had been referred for diagnostic exercise testing with simultaneous metabolic measurements. Only patients who completed an adequate test for maximum exertion manifested by a respiratory exchange ratio of > or = 1.10 were included in the study. RESULTS: The mean (+/- SD) body mass index (BMI) values for the three groups were 47.8 +/- 5.1, 30.1 +/- 5.7, and 33.8 +/- 9.0, respectively (p < 0.0001 for comparisons between morbidly obese patients and each comparator). The mean left ventricular ejection fraction for the heart failure group was 21.5 +/- 8.4%. Despite achieving higher peak heart rate and BP values, the morbidly obese patients had a mean maximum oxygen uptake (V(O2)max) that was similar to that of those with heart failure (17.8 +/- 3.6 vs 16.5 +/- 5.6 mL/kg/min, respectively; p = 0.14) and was considerably lower than that of the control group (17.8 +/- 3.6 vs 21.3 +/- 8.2 mL/kg/min, respectively; p = 0.007). In addition, among subjects in the control group, there was a graded inverse relation between BMI and V(O2)max. CONCLUSIONS: Morbidly obese individuals have severely reduced cardiorespiratory fitness that is similar to those with established systolic dysfunction heart failure. In addition, in those persons who are referred for stress testing for medical reasons, there is an inverse graded relationship between BMI and cardiorespiratory fitness. These data suggest that the impairment in V(O2)max in morbidly obese persons is related to BMI and possibly to other factors that impair peak cardiac performance. These findings are consistent with overall higher expected mortality in morbidly obese persons.

Coagulation and fibrinolytic responses to manual versus automated snow removal.

PURPOSE: The purpose of this study was to assess coagulation and fibrinolytic responses to snow removal. METHODS: Thirteen healthy male subjects (age = 26 +/- 5 yr, height = 179.0 +/- 7.0 cm, weight = 78.7 +/- 16.1 kg, .VO2max = 54.7 +/- 8.9 mL.kg-1.min-1) underwent maximal treadmill stress testing (TM), 10 min of snow shoveling (SS), and 10 min of snow removal using an automated snow thrower (ST). Blood was collected immediately before and after each test and analyzed for von Willebrand Factor antigen (vWF:ag), tissue plasminogen activator (tPA) antigen, and plasminogen activator inhibitor-1 (PAI-1) activity. Data were analyzed using a two-factor repeated-measures analysis of variance. RESULTS: vWF:ag significantly increased during TM (84.7 +/- 21.7% normal preexercise, 149.0 +/- 45.6% normal postexercise) but not SS or ST. TM resulted in significant increases in tPA antigen (6.54 +/- 2.76 ng.mL-1 preexercise, 21.39 +/- 10.56 ng.mL-1 postexercise) and both SS and TM caused significant reductions in PAI-1 activity (SS = 15.1 +/- 3.8 AU.mL-1 preexercise, 13.2 +/- 4.3 AU.mL-1 postexercise; TM = 15.3 +/- 3.6 AU.mL-1 preexercise, 10.5 +/- 5.3 AU.mL-1 postexercise). Postexercise PAI-1 activity was significantly lower for TM versus SS. tPA antigen was unchanged after SS and ST, and PAI-1 activity was unchanged after ST. CONCLUSION: vWF:ag is unchanged after self-paced snow shoveling and automated snow removal in young, healthy males. Snow shoveling acutely increases fibrinolytic potential in this population, although not to the degree observed after maximal treadmill exercise.