Methylphenidate and exercise: additive effects on motor performance, variable effects on the neuroendocrine response.

It has been suggested that the effects of intensive environmental stressors and of psychostimulant drugs may be interchangeable. A specific test of this hypothesis was undertaken in a double-blind, placebo controlled, cross-over study of the stimulant drug, methylphenidate (MPH), and of intense exercise, alone and in combination. On measures of motor performance the effects of MPH and of exercise were additive while on measures of neuroendocrine response the individual and interactive effects were variable. The effects of MPH and of intense exercise are probably mediated by mechanisms that overlap to a degree but are by no means identical.