Sweating responses to isometric handgrip exercise and forearm muscle metaboreflex in prepubertal children and elderly.
Sweating responses to isometric handgrip exercise and forearm muscle metaboreflex in prepubertal children and elderly.
复制标题
青春期前儿童和老年人对等长握力运动和前臂肌肉代谢反射的出汗反应。
作者：
Amano T;Kai S;Nakajima M;Ichinose-Kuwahara T;Gerrett N;Kondo N;Inoue Y
新发现本研究的中心问题是什么？非热因素（例如肌肉代谢反射）有助于运动期间的出汗反应。虽然众所周知，与年轻人相比，青春期前儿童和老年人因核心温度升高引起的出汗反应减弱，但不清楚这些人群中非热性出汗是否也减弱。主要发现及其重要性是什么？与年轻人相比，青春期前儿童在等长握力运动和单独肌肉代谢反射期间的非热出汗反应在全身以非均匀的方式减弱，但仅在老年人的肌肉代谢反射期间减弱。本研究的目的是探讨青春期前儿童和老年人等长握力（IH）运动和肌肉代谢反射的出汗反应。在炎热的天气里（环境温度，35°C;相对湿度，45%），13名健康年轻人，10名青春期前儿童和10名老年受试者（年龄分别为20.4 ± 1.2岁、11.4 ± 0.5岁和63.5 ± 3.1岁）重复了三次手握运动方案，包括15岁时1分钟IH运动，30或45%的最大随意收缩（MVC），然后运动后2分钟前臂闭塞。连续测量前额、胸部、前臂、大腿和手掌的局部出汗率（SR）（通气胶囊法）。青春期前儿童在45%MVC下进行IH运动时的前额SR显著低于年轻人（年轻人和儿童分别为0.26 ± 0.22和0.08 ± 0.15 mg cm− 2 min − 1;P< 0.05），但在任何运动强度下均不低于老年人。胸部的SR（年轻人和儿童分别为0.22 ± 0.22和−0.01 ± 0.05 mg cm− 2 min − 1），前臂（0.14 ± 0.12和0.03 ± 0.04 mg cm− 2 min −1）和大腿在45%MVC的运动后闭塞期间，儿童的平均血容量（0.13 ± 0.10和0.02 ± 0.03 mg cm− 2 min −1）显著低于年轻成人（P< 0.05）。老年受试者前臂的SR显著降低（年轻人和老年人为0.04 ± 0.04和0.01 ± 0.02 mg cm− 2 min − 1，分别）和大腿（0.07 ± 0.07和0.01 ± 0.03 mg cm− 2 min −1），15% MVC和45% MVC时大腿（0.13 ± 0.10和0.04 ± 0.04）mg cm− 2 min −1，与青年组比较有显著性差异（P< 0.05）。这些结果表明，出汗的IH运动和肌肉代谢反射的反应是不发达的青春期前的儿童和老化衰减的肌肉代谢反射的方式是不一致的整个身体。
New FindingsWhat is the central question of this study?Non‐thermal factors (e.g. muscle metaboreflex) contribute to the sweating response during exercise. Although it is well recognized that the sweating responses caused by core temperature elevation in prepubertal children and the elderly are attenuated compared with young adults, it is unknown whether non‐thermal sweating is also attenuated in these populations.What is the main finding and its importance?The non‐thermal sweating response during isometric hand‐grip exercise and isolated muscle metaboreflex were attenuated in prepubertal children compared with young adults in a non‐uniform manner over the body, but only during the muscle metaboreflex in the elderly. This may explain the maturation‐ and ageing‐related decline of sweating during exercise.The purpose of the present study was to investigate sweating responses to isometric hand‐grip (IH) exercise and muscle metaboreflex in prepubertal children and the elderly. In hot conditions (ambient temperature, 35°C; relative humidity, 45%), 13 healthy young adults, 10 prepubertal children and 10 elderly subjects (aged 20.4 ± 1.2, 11.4 ± 0.5 and 63.5 ± 3.1 years, respectively) repeated a three hand‐grip exercise protocol that consisted of 1 min IH exercise at 15, 30 or 45% of maximal voluntary contraction (MVC) followed by 2 min postexercise forearm occlusion. Local sweat rates (SRs) on the forehead, chest, forearm, thigh and palm were continuously measured (ventilated capsule method). The forehead SR in prepubertal children during IH exercise at 45% MVC was significantly lower than that of young adults (0.26 ± 0.22 and 0.08 ± 0.15 mg cm−2min−1for young adults and children, respectively;P< 0.05) but not of the elderly at any exercise intensities. The SR on the chest (0.22 ± 0.22 and −0.01 ± 0.05 mg cm−2min−1for young adults and children, respectively), forearm (0.14 ± 0.12 and 0.03 ± 0.04 mg cm−2min−1) and thigh (0.13 ± 0.10 and 0.02 ± 0.03 mg cm−2min−1) during postexercise occlusion at 45% MVC was significantly lower in children than in young adults (P< 0.05). Elderly subjects showed a significantly lower SR on the forearm (0.04 ± 0.04 and 0.01 ± 0.02 mg cm−2min−1for young adults and elderly, respectively) and thigh (0.07 ± 0.07 and 0.01 ± 0.03 mg cm−2min−1) at 15% MVC and on the thigh at 45% MVC (0.13 ± 0.10 and 0.04 ± 0.04 mg cm−2min−1) during postexercise occlusion compared with young adults (P< 0.05). These results suggest that sweating responses to IH exercise and muscle metaboreflex were underdeveloped in prepubertal children and that ageing attenuates the response to the muscle metaboreflex in a way that is not consistent across the body.