Exercise capacity in lean versus obese women

The aim of this study was to assess the nature and magnitude of the differe nces in submaximal and maximal exercise capacity parameters between lean an d obese women. A total of 225 healthy obese women 18-65 years (BMI> or=30 k g/m(2)) and 81 non-athletic lean women (BMI< or=26 kg/m(2)) were selected. Anthropometric measurements (weight and height), body composition assessmen t (bioelectrical impedance method) and a maximal exercise capacity test on a bicycle ergometer were performed. Oxygen uptake (VO2), carbon dioxide pro duction (VCO2), expired ventilation (VE), respiratory quotient (RQ), breath ing efficiency (VE/VO2), mechanical efficiency (ME) and anaerobic threshold (AT) were calculated. At a submaximal intensity load of 70 W,VO2 (1/min) w as larger in the obese women and was already 78% of their peak VO2, whereas in the non-obese it was only 69% (P=0.0001). VE (1/min) was larger, VE/VO2 did not differ and ME was lower in obese compared to the lean women. AT oc curred at the same percentage of peak VO2 in both lean and obese women. At peak effort, achieved load, terminal VO2 (1 min(-1) kg(-1)), VE, heart rate , RQ respiratory exchange ratio and perceived exertion were lower in obese subjects compared to the non-obese. Obese subjects mentioned significantly more musculoskeletal pain as a reason to end the test, whereas in lean subj ects it was leg fatigue. Lean women recovered better as after 2 min they we re already at 35% of the peak VO2, whereas in the obese women it was 47% (P =0.0001). Our results confirm that exercise capacity is decreased in obesit y, both at submaximal and peak intensity, and during recovery. Moreover, at peak effort musculoskeletal pain was an important reason to end the test a nd not true leg fatigue. These findings are important when designing exerci se programs for obese subjects.