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

Abstract

Purpose: 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.

Method: 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.

Results: 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.

Conclusions: 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;