Innland University of Applied Sciences, Lillehammer, Norway.
Faculty of Kinesiology, Cumming School of Medicine, University of Calgary, Calgary, Canada.
Exp Physiol. 2021 Jan;106(1):316-327. doi: 10.1113/EP088544. Epub 2020 Jul 4.
What is the central question of this study? Do haemoglobin mass and red blood cell volume increase in elite cyclists training in a hot environment compared to a control group training at normal temperature? What is the main finding and its importance? Five weeks of heat training increases haemoglobin mass in elite cyclists. There are small to intermediate effect sizes for exercise parameters favouring heat training.
In this study we tested the hypothesis that performing 1 h of regular light exercise in a heat chamber (HEAT; 37.8 ± 0.5°C; 65.4 ± 1.8% humidity) 5 times week for a total of 5 weeks increases haemoglobin mass (Hb ) and exercise performance in elite cyclists ( = 76.2 ± 7.6 ml min kg ). Twenty-three male volunteers were assigned to HEAT (n = 11) or CON (n = 12; 15.5 ± 0.1°C; 25.1 ± 0.0% humidity) training groups. Hb was determined before and after the intervention period in conjunction with an extensive exercise test protocol (conducted at 16-19°C). HEAT increased (P < 0.05) Hb by 42 g from 893 ± 78 to 935 ± 108 g whereas Hb remained unchanged (+6 g) in CON. Furthermore, statistical analysis revealed a time-group interaction (P < 0.05). The greater increase in Hb in HEAT, however, did not manifest in a greater increase in (225 ± 274 ml min in HEAT and 161 ± 202 ml min in CON). While HEAT reduced (P < 0.05) lactate levels during some of the submaximal exercise tests, there was no statistical difference between other performance parameters. There were, however, small to intermediate effect sizes favouring HEAT for lactate threshold power output (2.8 ± 3.9 vs. -0.4 ± 5.1% change, effect size (ES) = 0.34), gross economy in the fatigued state (0.19 ± 0.42 vs. -0.12 ± 0.49%-point change, ES = 0.52) and 15 min mean power (6.9 ± 8.4 vs. 3.4 ± 5.1% increase, ES = 0.22). This study demonstrates an increase in Hb and small to intermediate effect sizes on exercise variables in elite cyclists following a 5-week heat training intervention.
本研究的核心问题是什么？在炎热环境中进行训练的精英自行车手的血红蛋白质量和红细胞体积是否比在正常温度下训练的对照组增加？主要发现及其重要性是什么？5 周的热训练增加了精英自行车手的血红蛋白质量。支持热训练的运动参数具有小到中等的效果大小。
在这项研究中，我们检验了这样一个假设，即在热室（HEAT；37.8±0.5°C；65.4±1.8%湿度）中进行 1 小时的常规轻度运动，每周 5 次，总共 5 周，是否会增加血红蛋白质量（Hb）和精英自行车手的运动表现（n=76.2±7.6ml·min-1·kg-1）。23 名男性志愿者被分配到 HEAT（n=11）或 CON（n=12；15.5±0.1°C；25.1±0.0%湿度）训练组。在干预期前后，结合广泛的运动测试方案（在 16-19°C 下进行）确定了 Hb。HEAT 使 Hb 增加（P<0.05）42g，从 893±78g 增加到 935±108g，而 CON 中的 Hb 保持不变（增加 6g）。此外，统计分析显示时间组之间存在交互作用（P<0.05）。然而，HEAT 中 Hb 的更大增加并没有导致 （HEAT 中增加 225±274ml·min，CON 中增加 161±202ml·min）。虽然 HEAT 降低了（P<0.05）一些亚最大运动测试中的乳酸水平，但其他性能参数之间没有统计学差异。然而，对于乳酸阈功率输出（2.8±3.9 与-0.4±5.1%的变化，效应量（ES）=0.34）、疲劳状态下的总经济性（0.19±0.42 与-0.12±0.49%点的变化，ES=0.52）和 15 分钟平均功率（6.9±8.4 与 3.4±5.1%的增加，ES=0.22），HEAT 具有小到中等的效应量。这项研究表明，在进行为期 5 周的热训练干预后，血红蛋白质量增加，对精英自行车手的运动变量产生小到中等的影响。
