Thermal Ergonomics Laboratory, Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia.
Thermosense Lab, Environmental Ergonomics Research Centre, Loughborough University, Leicestershire, United Kingdom.
Am J Physiol Regul Integr Comp Physiol. 2021 Mar 1;320(3):R258-R267. doi: 10.1152/ajpregu.00090.2020. Epub 2020 Dec 9.
The purpose of this study is to determine whether thermoregulatory capacity is altered by multiple sclerosis (MS) during exercise in the heat. Sixteen MS participants (EDSS: 2.9 ± 0.9; 47 ± 8 yr; 77.6 ± 14.0 kg) and 14 healthy control (CON) participants (43 ± 11 yr; 78.6 ± 17.0 kg) cycled at a heat production of 4 W·kg for 60 min at 30°C, 30% relative humidity (RH) (Warm). A subset of eight MS (EDSS: 2.6 ± 0.5; 44 ± 8 yr; 82.3 ± 18.2 kg) and 8 CON (44 ± 12 yr; 81.2 ± 21.1 kg) also exercised at 35°C, 30% RH (Hot). Rectal temperature (T), mean skin (T) temperature, and local sweat rate (LSR) on the upper back (LSR) and forearm (LSR) were measured. All CON, and only 9 of 16 and 7 of 8 MS participants completed 60 min of exercise in Warm and Hot trials, respectively. All MS participants who were unable to complete exercise stopped with a ΔT between 0.2 and 0.5°C. The time to reach a ΔT of 0.2°C was similar (MS: 28 ± 15 min, CON: 32 ± 18 min; = 0.51). For MS participants, completing 60-min of exercise in Warm, ΔT ( = 0.13), ΔT ( = 0.45), LSR ( = 0.69), and LSR ( = 0.54) was similar to CON, but ΔT (body temperature) (MS: 0.16 ± 0.13°C, CON: 0.07 ± 0.06°C; = 0.02) and onset time (MS: 16 ± 10 min, CON: 8 ± 5 min; = 0.02) for sweating were greater in MS. Similarly, in Hot, ΔT ( = 0.52), ΔT ( = 0.06), LSR ( = 0.59), and LSR ( = 0.08) were similar, but ΔT (MS: 0.19 ± 0.16°C, CON: 0.06 ± 0.04°C; = 0.04) and onset time (MS: 13 ± 7 min, CON: 6 ± 3 min; = 0.02) for sweating were greater in MS. Even at 35°C, a delayed sweating onset did not alter heat loss to sufficiently affect exercise-induced rises in core temperature. Heat intolerance with MS does not seem attributable to thermoregulatory impairments.
本研究旨在确定多发性硬化症（MS）是否会在热环境下运动时改变体温调节能力。16 名 MS 参与者（EDSS：2.9±0.9；47±8 岁；77.6±14.0kg）和 14 名健康对照（CON）参与者（43±11 岁；78.6±17.0kg）在 30°C、30%相对湿度（RH）（温暖）下以 4W·kg 的产热量进行 60 分钟的自行车运动。8 名 MS （EDSS：2.6±0.5；44±8 岁；82.3±18.2kg）和 8 名 CON（44±12 岁；81.2±21.1kg）的子集也在 35°C、30%RH（热）下进行了运动。测量直肠温度（T）、平均皮肤温度（T）和上背部（LSR）和前臂（LSR）的局部出汗率（LSR）。所有 CON 和 16 名 MS 参与者中的 9 名和 8 名 MS 参与者中的 7 名分别完成了温暖和炎热试验中的 60 分钟运动。所有无法完成运动的 MS 参与者的 T 差值在 0.2 和 0.5°C 之间。达到 0.2°C T 差值的时间相似（MS：28±15 分钟，CON：32±18 分钟；=0.51）。对于 MS 参与者，在温暖条件下完成 60 分钟运动，ΔT（=0.13）、ΔT（=0.45）、LSR（=0.69）和 LSR（=0.54）与 CON 相似，但ΔT（体温）（MS：0.16±0.13°C，CON：0.07±0.06°C；=0.02）和出汗开始时间（MS：16±10 分钟，CON：8±5 分钟；=0.02）在 MS 中更大。同样，在炎热中，ΔT（=0.52）、ΔT（=0.06）、LSR（=0.59）和 LSR（=0.08）相似，但ΔT（MS：0.19±0.16°C，CON：0.06±0.04°C；=0.04）和出汗开始时间（MS：13±7 分钟，CON：6±3 分钟；=0.02）在 MS 中更大。即使在 35°C 下，出汗开始时间的延迟也不会改变散热，从而充分影响运动引起的核心温度升高。MS 导致的不耐热似乎不是由于体温调节受损所致。
