Effects of age and counseling on the cardiorespiratory response to graded exercise

To report on the normative cardiorespiratory response to a graded exercise test in a group of healthy males, 30-69 yr of age (n = 816), and to test the effect of health and fitness counseling on cardiorespiratory fitness in a subset of healthy subjects (n = 87, mean follow-up = 7.3 yr) who returned for at least five subsequent visits.

As part of a preventive medicine service, each subject performed an incremental exercise test to exhaustion on a treadmill. Peak oxygen consumption, ventilatory threshold, HRmax, and peak oxygen pulse were the primary dependent measures recorded from each test.

Both analyses (cross-sectional data followed by longitudinal data) showed a significant decline in peak oxygen consumption with age (0.03 and 0.04 L x min(-1) x yr(-1)), which was related to an age-associated decline in HRmax (0.97 and 0.81 beats per year) and peak oxygen pulse (0.13 and 0.08 mL per beat per year). Ventilatory threshold was also influenced by age, declining in both the cross-sectional (0.02 L x min(-1) x yr(-1)) and the longitudinal (0.03 L x min(-1) x yr(-1)) comparisons. However, when ventilatory threshold and peak oxygen pulse were analyzed for changes between the initial and the follow-up (7.3 yr) visits, no difference was found. It remains unclear if this finding can be attributed to the intervention used.

Our data support previous investigations on the effects of age on cardiorespiratory fitness. More work is needed to define the potential longitudinal benefits of interventions like those administered in the present study.