Between 21 and 34 years of age, aging alters the catecholamine responses to supramaximal exercise in endurance trained athletes

The purpose of this study was to determine the effect of aging and training on the adrenaline (A) and noradrenaline (NA) responses during the Wingate-test in three age groups of subjects: 21 year old untrained subjects (21U), 21 year old endurance trained (21T) (national elite runners), 34 year old endurance trained (34T) (national elite runners). Performances during the test were judged using the usual parameters of peak power (Wmax) and mean power (W) expressed in absolute or relative values. A and NA responses were measured at rest (A0 and NA0) immediately at the end of the exercise (Amax and NAmax) and after 5 minutes recovery (A5 and NA5). Plasma maximal lactate (La(max)) was determined 3 minutes after the end of the exercise. Wmax, W and La(max) were always significantly lower in 34T compared to 21T and 21U. The catecholamine responses were similar in 21T and 21U. Inversely, a significantly lower value of Amax was observed in 34T (2.01 +/- 0.5 nmol x l(-1)) compared to 21U (3.62 +/- 0.3 nmol x l(-1)) associated with a significantly higher value of NA(max) in 34T versus 21T and 21U. Thus, the Amax/NA(max) ratio was found to be significantly lower in the older subjects versus both 21T and 21U. All these findings indicated that endurance training did not affect the sympathoadrenergic responses to a supramaximal exercise and suggested that only one decade may reduce the capacity of the medulla to secrete adrenaline and therefore the adrenal medulla responsiveness to the sympathetic nervous activity.