Abstract
Ageing is associated with deterioration in the structure and function of the pulmonary circulation with a decrease in alveolar-capillary surface area. We asked whether age-related changes in the pulmonary circulation limit alveolar-capillary recruitment and gas exchange during exercise in healthy older adults. 5 old (OLD; 66±8 yr, VO2max 140±31% age-predicted) and 8 young adults (YNG; 28±2 yr, VO2max 131±17% age-predicted) participated. Lung diffusing capacity for carbon monoxide (DLCO), cardiac output (Q), pulmonary capillary blood volume (Vc) and membrane diffusing capacity (Dm) were measured via a rebreathe method at rest and during cycle exercise at 25, 50, 75 and 90% of peak power. SaO2 was measured throughout exercise via pulse oximetry. At rest, DLCO, Vc, and Dm were lower in the OLD vs. the YNG group (22.3±5.8 vs. 29.6±4.7 ml/min/mmHg, 70±26 vs.102±48 ml, 35.2±7.9 vs. 46.6±12.3 ml/min/mmHg, P<0.05). However, DLCO increased linearly with exercise intensity in both groups with no plateau or change in slope in DLCO with increasing Q (Fig. 1). Vc and Dm also increased with progressive exercise in both groups (Fig. 1). SaO2 did not change during exercise in either group.
These data suggest that the age-associated changes in the pulmonary circulation do not impair alveolar-capillary recruitment and gas exchange during exercise in healthy older adults. NIH HL71478
- © 2011 ERS