Variations in maximal oxygen intake with physical activity in middle-aged men.

SUMMARY Data on maximal exercise performance are presented for normal middle-aged men free of cardiovascular disease. Maximal oxygen intake, oxygen pulse, heart rate, and lactate levels all decrease with increasing age. Physical activity defined by habitual running of any amount had a highly significant effect on maximal oxygen consumption. The enhanced effect of physical activity was found equivalent to nearly 10 years of age effect on maximal aerobic capacity. Multivariate analysis revealed significant association between maximal oxygen intake and several coronary risk factors; specifically, physical activity, vital capacity, cigarette smoking, and body weight. Notably lacking in significance were other known risk factors, serum cholesterol, and blood pressure. Data for maximal oxygen intake on healthy men aged 40 to 70 years are presented by age group and physical activity class; and regression equations are provided for estimation of maximal oxygen intake from age, physical activity status, and duration of the multistage treadmill test. These data should prove useful as normal standards for assessment of aerobic capacity in middle-aged men until such time as larger numbers of data on maximal exercise testing become available. Age Blood pressure Coronary risk factors Exercise Cholesterol Vital capacity Cigarette smoking Weight FUNCTIONAL aerobic capacity (power) which is best defined by measurement of maximal oxygen intake1 varies with body weight, especially lean body mass," 2 physical activity status, and aging.3-'2 Usually measurement of maximal oxygen intake requires two or more tests of maximal exercise to demonstrate an asymptotic relationship between intake and work load.' It is of interest, therefore, to report that maximal oxygen intake can be measured in a single testing procedure, when a multistage treadmill test of uninterrupted submaximal and maximal exercise is utilized.13 The linear relationship between duration of effort and oxygen intake, under these testing conditions, varies in healthy middle-aged men with age and physical status. Accordingly, when these items are known, maximal oxygen intake may be estimated from observed duration of exertion. Methods Oxygen intake (Vo2) was measured during the last 2 to 4 minutes of treadmill exercise on 86 healthy middle-aged men (84 Caucasians, one Oriental, and one Negro) in the YMCA cohort. Expired air samples were collected at 1-min intervals in evacuated neoprene bags; volumes were measured in a calibrated gasometer and corrected to standard temperature and barometric pressure. Oxygen and carbon dioxide concentrations in aliquots from each bag were measured using micro-Scholander technic. The final minute of gas collection …