Determinants of Cardiorespiratory Fitness After Bariatric Surgery: Insights From a Randomised Controlled Trial of a Supervised Training Program

Background: Severely obese patients have decreased cardiorespiratory fitness (CRF) and poor functional capacity. Bariatric surgerye induced weight loss improves CRF, but the determinants of this improvement are not well known. We aimed to assess the determinants of CRF before and after bariatric surgery and the impact of an exercise training program on CRF after bariatric surgery. Methods: Fifty-eight severely obese patients (46.1 +/- 6.1 kg/m(2), 78% women) were randomly assigned to either an exercise group (n = 39) or usual care (n = 19). Exercise training was conducted from the 3rd to the 6th months after surgery. Anthropometric measurements, abdominal and mid-thigh computed tomographic scans, resting echocardiography, and maximal cardiopulmonary exercise testing was performed before bariatric surgery and 3 and 6 months after surgery. Results: Weight, fat mass, and fat-free mass were reduced significantly at 3 and 6 months, without any additive impact of exercise training in the exercise group. From 3 to 6 months, peak aerobic power (VO2peak) increased significantly (P < 0.0001) in both groups but more importantly in the exercise group (exercise group: from 18.6 +/- 4.2 to 23.2 +/- 5.7 mL/kg/min; control group: from 17.4 +/- 2.3 to 19.7 +/- 2.4 mL/kg/min; P value, group x time = 0.01). In the exercise group, determinants of absolute VO2peak (L/min) were peak exercise ventilation, oxygen pulse, and heart rate reserve (r(2) = 0.92; P < 0.0001), whereas determinants of VO2peak indexed to body mass (mL/kg/min) were peak exercise ventilation and early-to-late filling velocity ratio (r(2) = 0.70; P < 0.0001). Conclusions: A 12-week supervised training program has an additive benefit on cardiorespiratory fitness for patients who undergo bariatric surgery.