The effect of aging and cardiorespiratory fitness on the lung diffusing capacity response to exercise in healthy humans.
Aging is associated with deterioration in the structure and function of the pulmonary circulation. We characterized the lung diffusing capacity for carbon monoxide (DLCO), alveolar-capillary membrane conductance (DmCO), and pulmonary-capillary blood volume (Vc) response to discontinuous incremental exercise at 25, 50, 75, and 90% of peak work (Wpeak) in four groups: 1) Young [27 ± 3 yr, maximal oxygen consumption (V̇o2max): 110 ± 18% age predicted]; 2) Young Highly Fit (27 ± 3 yr, V̇o2max: 147 ± 8% age predicted); 3) Old (69 ± 5 yr, V̇o2max: 116 ± 13% age predicted); and 4) Old Highly Fit (65 ± 5 yr, V̇o2max: 162 ± 18% age predicted). At rest and at 90% Wpeak, DLCO, DmCO, and Vc were decreased with age. At 90% Wpeak, DLCO, DmCO, and Vc were greater in Old Highly Fit vs. Old adults. The slope of the DLCO-cardiac output (Q̇) relationship from rest to end exercise at 90% Wpeak was not different between Young, Young Highly Fit, Old, and Old Highly Fit (1.35 vs. 1.44 vs. 1.10 vs. 1.35 mlCO·mmHg-1·liter blood-1, P = 0.388), with no evidence of a plateau in this relationship during exercise; this was also true for DmCO-Q̇ and Vc-Q̇. V̇o2max was positively correlated with 1) DLCO, DmCO, and Vc at rest; and 2) the rest to end exercise change in DLCO, DmCO, and Vc. In conclusion, these data suggest that despite the age-associated deterioration in the structure and function of the pulmonary circulation, expansion of the pulmonary capillary network does not become limited during exercise in healthy individuals regardless of age or cardiorespiratory fitness level.NEW & NOTEWORTHY Healthy aging is a crucial area of research. This article details how differences in age and cardiorespiratory fitness level affect lung diffusing capacity, particularly during high-intensity exercise. We conclude that highly fit older adults do not experience a limit in lung diffusing capacity during high-intensity exercise. Interestingly, however, we found that highly fit older individuals demonstrate greater values of lung diffusing capacity during high-intensity exercise than their less fit age-matched counterparts.
['Coffman|Kirsten E|KE|', 'Carlson|Alex R|AR|', 'Miller|Andrew D|AD|', 'Johnson|Bruce D|BD|', 'Taylor|Bryan J|BJ|']
D000328:Adult D000368:Aged D000375:Aging D001810:Blood Volume D002196:Capillaries D002248:Carbon Monoxide D002302:Cardiac Output D000072599:Cardiorespiratory Fitness D015444:Exercise D005260:Female D006801:Humans D008168:Lung D008297:Male D010100:Oxygen D010101:Oxygen Consumption D011650:Pulmonary Alveoli D011652:Pulmonary Circulation D011653:Pulmonary Diffusing Capacity D012146:Rest
lung diffusing capacity pulmonary circulation alveolar-capillary membrane conductance pulmonary-capillary blood volume maximal aerobic capacity