ABSTRACT
Maximal oxygen uptake (Vo<SUB>2</SUB>max) and lactate threshold were measured during an incremental bicycle ergometer test in 40 healthy middle-aged and older runners between 43 and 79 years of age. Although the 10-km run time slowed with increasing age, there were no significant differences in recent training habits or relative amount of body fat between four age groups. However, our cross-sectional data revealed an annual decrement of -0.74 m<I>l</I>/kg/ min/yr, which was significantly greater than that reported in previous studies. Vo<SUB>2</SUB>max values for the runners were greater than those for sedentary men of similar ages by about 50% in each age group. Significant correlations were found between the age at the onset of running training and Vo<SUB>2</SUB>max (r=-0.600, p<0.05) . Vo<SUB>2</SUB>@LT declined significantly but less rapidly with age (r=0.686, p<0.05) than Vo<SUB>2</SUB>max. Both the mean maximal heart rate (HRmax) and HR@LT also declined with age. No significant differences in HRmax were observed between the runners and sedentary men of the respective age groups. Significant correlations were also found between the estimated HRmax and directly measured HRmax (r=0.600) . Neither systolic blood pressure nor diastolic blood pressure during submaximal-maximal exercise were found to increase with age. We suggest that maintenance of a higher lactate threshold in older runners when expressed as a percentage of Vo<SUB>2</SUB>max is attributable to a greater age-dependent decline in Vo<SUB>2</SUB>max with a smaller change in Vo<SUB>2</SUB>@LT.