Falk B, Bar-Or O, MacDougall J D
Children's Exercise and Nutrition Centre, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
J Appl Physiol (1985). 1991 Nov;71(5):1741-5. doi: 10.1152/jappl.1991.71.5.1741.
Thermoregulatory responses to exercise in the heat, especially sweating pattern, differ between children and adults. To determine whether such differences may be related to hormonal responses and to assess the possible association between this response and physical maturation, three groups of circumpubertal boys cycled at 50% of maximal O2 uptake (three 20-min bouts with 10 min of rest between bouts) in 42 degrees C at 20% relative humidity. On the basis of Tanner staging, 11 were prepubertal (PP), 12 midpubertal (MP), and 7 late pubertal (LP). Water ingestion was encouraged to minimize dehydration. Venous blood was sampled before and immediately after the session. Changes in heart rate, rectal temperature, and percent decrease in plasma volume did not differ among groups. There was no change in plasma osmolality in any of the groups. Resting testosterone concentrations were higher with increased level of physical maturity (PP = 0.4 +/- 0.1, MP = 8.2 +/- 1.9, LP = 13.8 +/- 1.2 nmol/l; P less than 0.05). In all groups, both aldosterone (ALD) and prolactin (PRL) markedly increased after exercise in the heat (ALD: PP = 161 +/- 40 vs. 1,289 +/- 263, MP = 173 +/- 47 vs. 1,245 +/- 153, LP = 250 +/- 76 vs. 1,681 +/- 400 pmol/l; PRL: PP = 8.1 +/- 1.2 vs. 24.9 +/- 4.2, MP = 8.8 +/- 1.0 vs. 22.0 +/- 8.9, LP = 8.4 +/- 0.8 vs. 39.0 +/- 3.6 micrograms/l; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
儿童和成人对热环境中运动的体温调节反应，尤其是出汗模式有所不同。为了确定这些差异是否可能与激素反应有关，并评估这种反应与身体成熟之间的可能关联，三组青春期前后的男孩在42摄氏度、相对湿度20%的环境下，以最大摄氧量的50%进行骑行（三次20分钟的运动，每次运动之间休息10分钟）。根据坦纳分期，11人为青春期前（PP），12人为青春期中期（MP），7人为青春期后期（LP）。鼓励摄入水分以尽量减少脱水。在运动前和运动结束后立即采集静脉血样。三组之间心率、直肠温度和血浆量减少百分比的变化没有差异。所有组的血浆渗透压均无变化。随着身体成熟度的提高，静息睾酮浓度升高（PP = 0.4 +/- 0.1，MP = 8.2 +/- 1.9，LP = 13.8 +/- 1.2 nmol/l；P < 0.05）。在所有组中，热环境运动后醛固酮（ALD）和催乳素（PRL）均显著增加（ALD：PP = 161 +/- 40 vs. 1,289 +/- 263，MP = 173 +/- 47 vs. 1,245 +/- 153，LP = 250 +/- 76 vs. 1,681 +/- 400 pmol/l；PRL：PP = 8.1 +/- 1.2 vs. 24.9 +/- 4.2，MP = 8.8 +/- 1.0 vs. 22.0 +/- 8.9，LP = 8.4 +/- 0.8 vs. 39.0 +/- 3.6 micrograms/l；P < 0.05）。（摘要截断于250字）
