Respiratory effects of obesity on the ventilatory response to exercise in older adults: the impact of a shift in operational lung volumes.

We examined the exercise ventilatory response to heavy exercise (ventilation [V̇E] and carbon dioxide elimination [V̇CO2] relationship from ventilatory threshold to peak exercise) and operational lung volumes (end expiratory [EELV] and end inspiratory [EILV]) in older adults with and without obesity. Forty-nine older adults with (BMI: 33.9 ± 5.0 kg/m2, age: 70 ± 2 y) and without obesity (BMI: 24.6 ± 3.0 kg/m2, age:71 ± 3 y) were evaluated, and performed a maximal incremental cycling test. The V̇E/V̇CO2 slope was lower in those with (43.1 ± 8.0) vs. without obesity (51.4 ± 11.1). While EELV was lower in those with (52.4 ± 6.1 %TLC) vs. without obesity (58.9 ± 5.8 %TLC), EILV was similar (with obesity: 88.2 ± 4.5 vs. without obesity: 89.2 ± 4.2 %TLC) between groups. EELV increased more from rest to peak exercise in those with obesity (0.23 ± 0.30 L: vs. -0.1 ± 0.4 L). Our findings demonstrate that the ventilatory response to heavy exercise is blunted in older adults with obesity, which appears to be associated with an increasing EILV encroaching on TLC.