title: Influence of forearm muscle metaboreceptor activation on sweating and cutaneous vascular responses during dynamic exercise.
abstract: We examined whether the sustained activation of metaboreceptor in forearm during cycling exercise can modulate sweating and cutaneous vasodilation. On separate days, 12 young participants performed a 1.5-min isometric handgrip exercise at 40% maximal voluntary contraction followed by 1) 9-min forearm ischemia (Occlusion, to activate metaboreceptor) or 2) no ischemia (Control) in thermoneutral conditions (27°C, 50%) with mean skin temperature clamped at 34°C. Thirty seconds after the handgrip exercise, participants cycled for 13.5 min at 40% V̇o2 max For Occlusion, forearm ischemia was maintained for 9 min followed by no ischemia thereafter. Local sweat rate (SR, ventilated capsule) and cutaneous vascular conductance (CVC, laser-Doppler perfusion units/mean arterial pressure) on the contralateral nonischemic arm as well as esophageal and skin temperatures were measured continuously. The period of ischemia in the early stages of exercise increased SR (+0.03 mg·cm(-2)·min(-1), P < 0.05) but not CVC (P > 0.05) above Control levels. No differences were measured in the esophageal temperature at which onset of sweating (Control 37.19 ± 0.09 vs. Occlusion 37.07 ± 0.09°C) or CVC (Control 37.21 ± 0.08 vs. Occlusion 37.08 ± 0.10°C) as well as slopes for these responses (all P > 0.05). However, a greater elevation in SR occurred thereafter such that SR was significantly elevated at the end of the ischemic period relative to Control (0.37 ± 0.05 vs. 0.23 ± 0.05 mg·cm(-2)·min(-1), respectively, P < 0.05) despite no differences in esophageal temperature. We conclude that the activation of forearm muscle metaboreceptor can modulate sweating, but not CVC, during cycling exercise without affecting the core temperature-SR relationship.
authors.affiliation: Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan;
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Amano
authors.affiliation: Human Integrative Physiology Laboratory, School of Business Administration, Meiji University, Tokyo, Japan;
authors.forename: Masashi
authors.initials: M
authors.lastname: Ichinose
authors.affiliation: Laboratory for Human Performance Research, Osaka International University, Osaka, Japan;
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Institute of Health and Sports Science, University of Tsukuba, Tsukuba, Japan;
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishiyasu
authors.affiliation: Applied Physiology Laboratory, Kobe Design University, Kobe, Japan; and.
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Koga
authors.affiliation: Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada.
authors.forename: Glen P
authors.initials: GP
authors.lastname: Kenny
authors.affiliation: Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan; kondo@kobe-u.ac.jp.
authors.forename: Narihiko
authors.initials: N
authors.lastname: Kondo
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002628:Chemoreceptor Cells / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D005542:Forearm / Q000502:physiology; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D012867:Skin / Q000098:blood supply*; D012881:Skin Temperature / Q000502:physiology; D013546:Sweating / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*
keywords: cutaneous active vasodilation; eccrine sweat gland; group III and IV muscle afferents