Exercise is a potent stimulus for the release of human growth hormone (hGH), but the time course of the hGH response to sprint exercise has not been studied.
The aim of the present study was to determine the time course of the hGH response to a 6 s and a 30 s maximal sprint on a cycle ergometer.
Nine males completed two trials, on one occasion performing a single 6 s sprint and on another a single 30 s sprint.
They then rested on a couch for 4 h while blood samples were obtained. Three of the participants completed a further control trial involving no exercise.
Metabolic responses were greater after the 30 s sprint than after the 6 s sprint. The highest measured mean serum hGH concentrations after the 30 s sprint were more than 450% greater than after the 6 s sprint (18.5 +/- 3.1 vs 4.0 +/- 1.5 microg l(-1), P