Faculty of Health, School of Exercise and Nutrition Sciences, Queensland University of Technology (QUT), A Wing O Block, Victoria Park Road, Kelvin Grove, QLD, 4059, Australia.
School of Exercise and Nutrition Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia.
Eur J Appl Physiol. 2020 Dec;120(12):2611-2624. doi: 10.1007/s00421-020-04482-7. Epub 2020 Aug 31.
To determine the vastus lateralis muscle temperature kinetics during and after passive heating, to exam the effect of sex on thermoregulatory responses, and the thermal safety and tolerance of the 42 °C hot-water immersion protocol.
Thirty participants (15 males, 15 females) underwent a 2 h 42 ºC hot-water immersion to the waist level. Vastus lateralis, rectal and skin temperature, thermal sensation, heart rate and blood pressure (BP) were measured during the passive heating and recovery period. Participant recovery was monitored until muscle temperature returned to baseline.
Vastus lateralis temperature increased to a maximal value of 39.0 ± 0.11 °C (P < 0.001), reaching a plateau after ~ 83.5 min of hot-water immersion and returning to baseline after ~ 115.8 min of recovery. Despite the anthropometric differences between males and females (e.g., height, body mass, body fat %, and fat thickness; P < 0.05), thermoregulatory responses showed no differences between sexes (P > 0.05). No change was found in systolic BP (~ 117 mmHg; P = 0.061). Peak rectal temperature (38.8 ± 0.14 °C; P < 0.001), heart rate (~ 100 bpm; P < 0.001), and diastolic BP (↓ ~ 13 mmHg; P < 0.001) during the hot-water immersion indicated the safety of the protocol. While skin temperature (~ 35.4 °C; P < 0.001) and thermal sensation (~ 5.95 AU; P < 0.001) confirmed protocol tolerance.
These data demonstrate lower-body 42 °C hot-water immersion to increase vastus lateralis temperature and plateau ~ 2.8 °C above baseline. This amplitude of muscle temperature change aligns with reported cellular adaptation and muscle growth. Thermal strain incurred from this protocol appears safe and tolerable, positioning it well for health-related prescription.
确定被动加热过程中和加热后股外侧肌的温度变化，研究性别对体温调节反应的影响，以及 42°C 热水浸泡方案的热安全性和耐受性。
30 名参与者（15 名男性，15 名女性）接受 2 小时 42°C 热水至腰部水平的浸泡。在被动加热和恢复期测量股外侧肌、直肠和皮肤温度、热感觉、心率和血压（BP）。监测参与者的恢复情况，直到肌肉温度恢复到基线。
股外侧肌温度升高到 39.0±0.11°C 的最大值（P<0.001），在热水浸泡后约 83.5 分钟达到平台期，在恢复后约 115.8 分钟恢复到基线。尽管男性和女性在人体测量学方面存在差异（例如身高、体重、体脂百分比和脂肪厚度；P<0.05），但性别之间的体温调节反应没有差异（P>0.05）。收缩压没有变化（117mmHg；P=0.061）。在热水浸泡期间，直肠温度峰值（38.8±0.14°C；P<0.001）、心率（100bpm；P<0.001）和舒张压（↓13mmHg；P<0.001）表明方案安全。而皮肤温度（35.4°C；P<0.001）和热感觉（~5.95 AU；P<0.001）证实方案耐受。
这些数据表明，下半身 42°C 热水浸泡可增加股外侧肌温度并使其比基线高出~2.8°C 达到平台期。这种肌肉温度变化的幅度与报告的细胞适应和肌肉生长一致。该方案引起的热应激似乎安全且耐受，非常适合与健康相关的处方。
