Short-term modulation of the exercise ventilatory response in older men.
During exercise with added dead space (DS), the exercise ventilatory response (DeltaV(E)/ DeltaV(CO(2))) is augmented in younger men, via short-term modulation (STM) of the exercise ventilatory response. We hypothesized that STM would be diminished or absent in older men due to age-related changes in respiratory function and ventilatory control. Men were studied at rest and during cycle exercise with and without added DS. DeltaV(E)/ DeltaV(CO(2)) increased progressively with increasing DS volume (p<0.01), such that CO(2) was not retained with added DS versus without. Hence, the increase in DeltaV(E)/ DeltaV(CO(2)) was not due to increased chemoreceptor feedback from rest to exercise. Increasing exercise intensity diminished the DeltaV(E)/ DeltaV(CO(2)) (p<0.01), and the size of this effect varied by DS volume (p<0.05). We conclude that STM of the exercise ventilatory response is robust in older men; hence, despite age-related changes in lung function and ventilatory control, the exercise ventilatory response can still adapt to increased DS, in order to maintain isocapnia during exercise relative to rest.
Wood
Helen E
HE
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, and University of Texas Southwestern Medical Center-Dallas, 7232 Greenville Ave., Dallas, TX 75231, United States. helen.wood@kcl.ac.uk
Mitchell
Gordon S
GS
Babb
Tony G
TG
D000368:Aged; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D005082:Physical Exertion / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology*