Stokes Keith, Nevill Mary, Frystyk Jan, Lakomy Henryk, Hall George
Sport and Exercise Science Group, School for Health, University of Bath, UK.
J Appl Physiol (1985). 2005 Oct;99(4):1254-61. doi: 10.1152/japplphysiol.00839.2004. Epub 2005 May 26.
This study examined the growth hormone (GH) response to repeated bouts of sprint cycling. Eight healthy men completed three trials consisting of two 30-s sprints on a cycle ergometer separated by either 60 min (Trial A) or 240 min (Trial B) of recovery and a single 30-s sprint carried out the day after Trial B (Trial C). Trials A and B were separated by at least 7 days. Blood samples were obtained at rest and during recovery from each sprint. In Trial A, GH was elevated immediately before sprint 2, and there was no further increase in GH following the second sprint [area under the curve: 460 (SD 348) vs. 226 min.mug(-1).l(-1) (SD 182), P = 0.05]. Free insulin-like growth factor I tended to be lower immediately before sprint 2 than sprint 1 (P = 0.06). Serum free fatty acids were not different immediately before each of the sprints. In Trial B, there was a trend for a smaller GH response to the second sprint [GH area under the curve: 512 (SD 396) vs. 242 min.mug(-1).l(-1) (SD 190), P = 0.09]. Free insulin-like growth factor I tended to be lower (P = 0.06), and serum free fatty acids were higher (P = 0.01) immediately before sprint 2 than sprint 1. There was no difference in the GH response to sprinting on consecutive days (Trials B and C). In conclusion, repeated bouts of sprint cycling on the same day result in an attenuation or even ablation of the exercise-induced increase in GH, depending on the recovery interval between sprints.
本研究检测了短跑自行车运动反复进行时生长激素（GH）的反应。八名健康男性完成了三项试验，包括在自行车测力计上进行两次30秒的冲刺，两次冲刺之间分别有60分钟（试验A）或240分钟（试验B）的恢复时间，以及在试验B后一天进行一次30秒的冲刺（试验C）。试验A和试验B间隔至少7天。在每次冲刺前休息时及恢复过程中采集血样。在试验A中，第二次冲刺前GH立即升高，第二次冲刺后GH没有进一步升高[曲线下面积：460（标准差348）对226分钟·微克⁻¹·升⁻¹（标准差182），P = 0.05]。游离胰岛素样生长因子I在第二次冲刺前往往比第一次冲刺前更低（P = 0.06）。每次冲刺前血清游离脂肪酸无差异。在试验B中，第二次冲刺时GH反应有变小的趋势[GH曲线下面积：512（标准差396）对242分钟·微克⁻¹·升⁻¹（标准差190），P = 0.09]。游离胰岛素样生长因子I往往更低（P = 0.06），且血清游离脂肪酸在第二次冲刺前比第一次冲刺前更高（P = 0.01）。连续两天进行冲刺（试验B和试验C）时GH反应无差异。总之，同一天反复进行短跑自行车运动导致运动诱导的GH升高减弱甚至消失，这取决于冲刺之间的恢复间隔。
