School of Applied Sciences, Edinburgh Napier University, Edinburgh, UK.
Oxid Med Cell Longev. 2018 May 9;2018:3402143. doi: 10.1155/2018/3402143. eCollection 2018.
The purpose of this study was to investigate the physiological and immunological response of highly trained runners to an intense bout of exercise performed at two different times of day, in a hot, humid environment.
Using a crossover randomized design, 13 highly trained runners (range [Formula: see text] 64-79 ml·kg min) performed a 10 km time trial run in hot (28°C) and humid conditions (70%), at 2 different times of day (09:00 hs and 18:00 hs). Venous blood samples were taken to determine WBCs (white blood cells), IL-6 (interleukin-6), CC16 (club cell protein 16), and HSP70 (heat shock protein-70) concentrations. Upper respiratory tract inflammation was additionally assessed using a nasal lavage procedure.
A significant diurnal difference ( < 0.05) was found for core body temperature, total WBC, and neutrophil and lymphocyte concentrations with higher values at 18:00 hs. A phase response in IL-6, HSP70, WBC, neutrophil, lymphocyte, and CC16 was noted, being more pronounced at 18:00 hs, whilst core body temperature and HR phase responses were more pronounced at 09:00 hs.
In hot and humid conditions, athletes may wish to consider, when possible, racing and particularly training in the morning where the least homeostatic perturbation occurs.
本研究旨在探讨在炎热、潮湿的环境中，两次不同时间进行高强度运动对训练有素的跑步者的生理和免疫反应的影响。
采用交叉随机设计，13 名训练有素的跑步者（年龄范围为[公式：见文本]64-79 ml·kg·min）在炎热（28°C）和高湿度（70%）条件下进行 10km 计时赛。在两个不同的时间点（09:00 时和 18:00 时）进行。采集静脉血样，以确定白细胞（WBC）、白细胞介素-6（IL-6）、CC16（肺泡细胞蛋白 16）和 HSP70（热休克蛋白-70）的浓度。还通过鼻冲洗程序评估上呼吸道炎症。
核心体温、总白细胞计数、中性粒细胞和淋巴细胞浓度存在明显的昼夜差异（<0.05），18:00 时的数值更高。IL-6、HSP70、WBC、中性粒细胞、淋巴细胞和 CC16 的相位反应明显，18:00 时更为明显，而核心体温和 HR 相位反应则更为明显在 09:00 时。
在炎热和潮湿的环境中，运动员可能希望尽可能在早上比赛和训练，因为此时体内平衡的干扰最小。
