BASAL AND EXERCISE-INDUCED CHANGES IN PLASMA-CATECHOLAMINES - RELATIONSHIP TO AGE, SMOKING-HABITS AND SAMPLING TIMES

Contrary to earlier investigations, we have previously shown that the initial increase in venous plasma noradrenaline (NA) during exercise d id not differ in young and elderly non-smoking subjects exercising at the same relative workload (75%), and that the greatest increase at ma ximal workload was observed in the young subjects. In order to determi ne whether the observed discrepancy could be explained by long-term sm oking, plasma NA and adrenaline (A) were evaluated in eight elderly ma le smokers (mean age 67 years). The results were compared with data re ported previously [Jensen et al. (1994) Exercise-induced changes in pl asma catecholames and neuropeptide Y: relation to age and sampling tim es. J Appl Physiol, 76, 1269-1273] in seven young (mean age 27 years) and seven elderly (mean age 61 years) non-smoking male subjects. As sh own earlier, basal plasma NA was significantly increased in elderly sm okers compared to young and elderly non-smokers. During exercise at 75 % of maximal work capacity, no difference was observed between elderly smokers and non-smokers. No difference in plasma A was found between elderly smokers and non-smokers either at rest or during exercise. The se findings indicate that the exercise-induced increase in plasma NA d id not differ in elderly smokers and non-smokers despite increased res ting levels in the former group, and that the increase in the elderly subjects was not augmented compared to that in young subjects.