title: Sweating responses and the muscle metaboreflex under mildly hyperthermic conditions in sprinters and distance runners.
abstract: To investigate the effects of different training methods on nonthermal sweating during activation of the muscle metaboreflex, we compared sweating responses during postexercise muscle occlusion in endurance runners, sprinters, and untrained men under mild hyperthermia (ambient temperature, 35°C; relative humidity, 50%). Ten endurance runners, nine sprinters, and ten untrained men (maximal oxygen uptakes: 57.5 ± 1.5, 49.3 ± 1.5, and 36.6 ± 1.6 ml·kg(-1)·min(-1), respectively; P < 0.05) performed an isometric handgrip exercise at 40% maximal voluntary contraction for 2 min, and then a pressure of 280 mmHg was applied to the forearm to occlude blood circulation for 2 min. The Δ change in mean arterial blood pressure between the resting level and the occlusion was significantly higher in sprinters than in untrained men (32.2 ± 4.4 vs. 17.3 ± 2.6 mmHg, respectively; P < 0.05); however, no difference was observed between distance runners and untrained men. The Δ mean sweating rate (averaged value of the forehead, chest, forearm, and thigh) during the occlusion was significantly higher in distance runners than in sprinters and untrained men (0.38 ± 0.07, 0.19 ± 0.03, and 0.11 ± 0.04 mg·cm(-2)·min(-1), respectively; P < 0.05) and did not differ between sprinters and untrained men. Our results suggest that the specificity of training modalities influences the sweating response during activation of the muscle metaboreflex. In addition, these results imply that a greater activation of the muscle metaboreflex does not cause a greater sweating response in sprinters.
authors.affiliation: Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Amano
authors.forename: Masashi
authors.initials: M
authors.lastname: Ichinose
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Koga
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Inoue
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishiyasu
authors.forename: Narihiko
authors.initials: N
authors.lastname: Kondo
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005334:Fever / Q000503:physiopathology*; D018737:Hand Strength / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007511:Ischemia / Q000503:physiopathology; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D012018:Reflex / Q000502:physiology*; D012420:Running / Q000502:physiology*; D012879:Skin Physiological Phenomena; D012881:Skin Temperature / Q000502:physiology; D013546:Sweating / Q000502:physiology*; D013696:Temperature