Pulmonary function and aerobic capacity in asymptomatic bariatric candidates with very severe morbid obesity

Aerobic capacity and respiratory function may be compromised in obesity, but few studies have been done in highly obese bariatric candidates. In a prospective study, these variables were documented in the preoperative period, aiming to define possible physiologic limitations in a apparently healthy and asymptomatic population.

Forty-six consecutively enrolled adults (age 39.6 +/- 8.4 years, 87.0% females, body mass index /BMI 49.6 +/- 6.3 kg/m2) were analyzed. Ventilatory variables were investigated by automated spirometry, aerobic capacity was estimated by a modified Bruce test in an ergometric treadmill, and body composition was determined by bioimpedance analysis.

Total fat was greatly increased (46.4 +/- 4.6% of body weight) and body water reduced (47.3 +/- 4.6 % body weight), as expected for such obese group. Spirometric findings including forced vital capacity of 3.3 +/- 0.8 L and forced expiratory volume-1 second of 2.6 +/- 0.6 L were usually acceptable for age and gender, but mild restrictive pulmonary insufficiency was diagnosed in 20.9%. Aerobic capacity was more markedly diminished, as reflected by very modest maximal time (4.5 +/- 1.1 min) and distance (322 +/-142 m) along with proportionally elevated maximal oxygen consumption (23.4 +/- 9.5 mL/kg/min) achieved by these subjects during test exercise.

1) Cardiopulmonary evaluation was feasible and well-tolerated in this severely obese population; 2) Mean spirometric variables were not diminished in this study, but part of the population displayed mild restrictive changes; 3) Exercise tolerance was very negatively influenced by obesity, resulting in reduced endurance and excessive metabolic cost for the treadmill run; 4) More attention to fitness and aerobic capacity is recommended for seriously obese bariatric candidates;