Abstract

Two groups of middle-aged male subjects (both N=11), one active (mean age 44.6 years) and one sedentary (mean age 43.7 years), undertook a graded exercise stress test on a bicycle ergometer in the post-absorptive state. Blood serum corticosteroid levels were measured at the following stages of metabolism; at rest, under conditions of submaximal and "maximal' exercise and during recovery. The active group showed no significant change in mean serum corticosteroid levels from resting values, during exercise and recovery. However the sedentary group displayed a significant increase in mean serum corticosteroid levels from a resting value of 5.81 plus or minus 0.41 mub-g/100 ml. (mean plus or minus S.E.) to 7.83 plus or minus 0.71 mug/100 ml. during "maximal' exercise (p smaller than 0.05), which was maintained throughout recovery 7.82 plus or minus 0.70 ug/100 ml (p smaller than 0.05). Futhermore the active group demonstrated significantly lower mean serum corticosteroid levels compared with the sedentary group under conditions of submaximal (p smaller than 0.05) and "maximal' (p smaller than 0.01) exercise and during recovery (p smaller than 0.01). It was concluded that the variability in the response patterns of serum corticosteroids during exercise stress in active and sedentary middle-aged males, reflected the physiological differences observed between the two groups of subjects.