PURPOSE:This study compares the responses of 20 male patients (mean age 51 +/- 11 years) with stable heart failure during peak and submaximal arm and leg exercise.METHODS:On day 1, subjects completed two symptom-limited graded exercise tests, one with their arms and one with their legs. On day 2, subjects performed arm only and leg only exercise at a matched power output of 30 Watts (W). Ten age-matched healthy subjects served as controls.RESULTS:During peak arm exercise power output, oxygen consumption (VO2), ventilation, and rate-pressure product were higher in healthy subjects than in patients with heart failure. However, when a subject's peak VO2 or power output during arm exercise was expressed as a percentage of that achieved during peak leg exercise, no significant differences were noted between patients with heart failure and healthy subjects. Among both groups, rate-pressure product, VO2, ventilation, the ventilatory equivalent for O2, and respiratory exchange ratio were all higher when exercising at 30 W with the arms versus 30 W with the legs. Also, in patients with heart failure heart rate was higher (+6 min-1) and stroke volume index lower (-4 mL/m2) during submaximal arm than leg exercise.CONCLUSIONS:Although peak exercise capacity (Watts, VO2) during arm exercise is lower in patients with heart failure than healthy subjects, when expressed as a percentage of peak leg capacity, the extent of the exercise intolerance they experience during arm exercise does not differ from healthy subjects.

This study determined the metabolic responses to different exercise:rest protocols during circuit exercise using hydraulic resistance. In experiment 1, nine subjects underwent nine different 27 min exercise circuits. There were three variations of three exercise:rest protocols (2:1, 1:1, 1:2). The VO2 for the nine circuits averaged (mean +/- SEM) 1.94 +/- 0.03 l.min-1 (43% of treadmill VO2max), with the largest difference between the protocols being 13%. Heart rate averaged 152.2 +/- 3.1 beats.min-1, with the largest difference between the protocols being 8%. Increasing the exercise duration per minute or the number of exercise bouts per minute had minimal effects on the mean VO2 and heart rate response to hydraulic resistive exercise. In experiment 2, nine subjects underwent three different 9 min exercise circuits using exercise:rest protocols of 2:1, 1:1, and 1:2 while work and VO2 were simultaneously measured. Surprisingly, increases in work were not necessarily accompanied by corresponding increases in VO2.

The incidence of coronary heart disease risk factors and the effects of 20 weeks of diet and exercise were studied in 36 obese adolescents. Values for the following risk factors were determined: serum triglyceride level, high-density lipoprotein-cholesterol level, total cholesterol level, systolic and diastolic BP, maximum work capacity, obesity, and presence of coronary heart disease in the family history. Of the subjects, 97% had four or more risk factors. Two subjects possessed all eight risk factors. The adolescents were randomly assigned to either a control, diet therapy and behavior change, or exercise, diet therapy, and behavior change group. From pre- to posttreatment, a 14.8% and 41.4% reduction in multiple risk was noted for the latter two groups, respectively. No significant difference between the control group and the diet and behavior change group was found. In contrast, the exercise-diet-behavior change group reduced multiple risk (P less than .01) more than either of the other groups. It was concluded that obese adolescents are at high risk for the development of coronary heart disease and that exercise in addition to moderate dietary restriction can result in the reduction of multiple coronary heart disease risk.

To assess the individual and combined effects of weight loss and weight training on body weight and body composition, 40 obese women were randomly assigned to one of four groups for an 8 wk weight-loss study. These groups were control (C); diet without exercise (DO); diet plus weight training (DPE); and weight training without diet (EO). Body weight decreased for DO (-4.47 kg) and DPE (-3.89 kg) compared with C (-0.38 kg) and EO (0.45 kg). Lean body weight (LBW) increased for EO (1.07 kg) compared with DO (-0.91 kg) and C (-0.31 kg) and for DPE (0.43 kg) compared with DO. Upper-arm muscle areas (determined by radiograph) increased for DPE (11.2 cm2) and EO (10.4 cm2) compared with C (2.7 cm2) and DO (2.1 cm2). It was concluded that weight training results in comparable gains in muscle area and strength for DPE and EO. Adding weight training exercise to a caloric restriction program results in maintenance of LBW compared with DO.

Ballor, D. L.; Katch, V. L.; Moorehead, C. P.; Becque, M. D.; Marks, C. R. Author Information

BECQUE, M. D.; KATCH, V. L.; DYER, R. M.; MARKS, C. R.; BALLOR, D. L. Author Information

Osteopetrosis is a metabolic bone disease characterized by excessive accumulation of skeletal mass due to a reduction in bone resorption. The pathogenesis of osteopetrosis is reduced osteoclast function. Reports of osteoclast numbers in several mammalian mutations exhibiting osteopetrosis have shown them to be increased, decreased, or normal in numbers. The present investigation quantitated the osteoclast populations and examined the cytology of osteoclasts by light microscopy in calvarial and tibial sites in one rabbit and two mouse mutations and compared them with their normal littermates.