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 t est were judged using the usual parameters of peak power ((W) over dot(max) ) and mean power ((W) over bar) expressed in absolute or relative values. A and NA responses were measured at rest (A(0) and NA(0)) immediately at the end of the exercise (A(max) and NA(max)) and after 5 minutes recovery (A(5 ) and NA(5)). Plasma maximal lactate (La-max) was determined 3 minutes afte r the end of the exercise. (W) over dot(max), (W) over bar and La-max were always significantly lower in 34T compared to 21T and 21U. The catecholamin e responses were similar in 21T and 21U. Inversely, a significantly lower v alue of A(max) 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 valu e of NA(max) in 34T versus 21T and 21U. Thus, the A(max)/NA(max) ratio was found to be significantly lower in the older subjects versus both 21T and 2 1U. 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 adrenali ne and therefore the adrenal medulla responsiveness to the sympathetic nerv ous activity.