Abstract
The aim of this study was to determine if 3-wks of short-term, high-intensity exercise training (HIT) alters growth hormone (GH) release. Nineteen recreationally active males (Mean + or - SD) (age = 24.9 + or - 3.9 yrs, BF% = 20.1 + or - 7.7) participated in this study. Each subject completed a 2-hr resting profile and a 2-hr acute sprint (AS) profile that consisted of one maximal 30-sec Wingate sprint on a cycle ergometer after 30 min of rest. Blood samples were taken every 15 min [Q15] during rest and more frequently [Q1-Q10] immediately following the sprint. Short-term, HIT consisted of 4-6 repetitions of 30-sec maximal sprints relative to body mass, 3 times times wk super(-1) with an additional AS profile at the end of each week of training for 3 wks. Peak power (PP) and fatigue index (FI) significantly increased while mean power (MP), minimum power (MinP), time to peak power (TTPP), and total work per sprint (TW) were unchanged after 3 wks of HIT. Total body mass significantly increased and was confirmed by a significant increase in lean mass of the lower extremities. Growth hormone area under the curve (AUC) and peak GH were significantly decreased after the first week of HIT despite no change in time to reach peak GH. One week of HIT significantly decreased GH release, with a simultaneous significant increase in anaerobic power and lean body mass of the lower extremities.