Weight loss, not aerobic exercise, improves pulmonary function in older obese men

Background. We evaluated the effect of weight loss (WL) or aerobic exercise (AEX) on pulmonary function in middle-aged and older (46-80 years) obese, sedentary men to determine the effect of reductions in body weight and increases in cardiorespiratory fitness on pulmonary function. Methods. Subjects were randomly assigned to WL (n = 73), AEX (n = 71), or control (n = 26) groups. Maximal oxygen uptake ((V) over dot O(2)max), body composition and anthropometrics, pulmonary function, and arterial blood gases were measured at baseline and after interventions. Results. The 35 subjects who completed WL decreased weight by 11%, body far percentage by 21% (p <.001), waist circumference by 8%. waist-hip ratio by 2%, and fat-fret mass by 3% (p <.05). This resulted in a 3% increase in forced vital capacity (FVC) (4.08 +/- 0.71 L vs 4.21 +/- 0.76 L), a 5% increase in total lung capacity (6.62 +/- 0.99 L vs 6.94 +/- 0.99 L), an 18% increase in functional residual capacity (3.09 +/- 0.58 L vs 3.66 +/- 0.79 L), and an 8% increase in residual volume (2.20 +/- 0.44 L vs 2.37 +/- 0.52 L), with no change in forced expiratory volume in one second (FEV1), FEV1/FVC ratio, or carbon monoxide diffusing capacity. The change in RVC correlated with change in body weight Cr = -.34. p<.05). The 38 subjects who completed AEX increased (V) over dotO(2)max by 14%, with no change in pulmonary function. There were no changes in 8 control subjects. Conclusions, WL changes static lung volumes, not dynamic pulmonary function, in middle-aged and older, moderately obese, sedentary men. Some of the alterations in static lung function associated with aging may be due to the development of obesity and are modifiable by WL.