title: Thermal sensation during mild hyperthermia is modulated by acute postural change in humans.
abstract: Thermal sensation represents the primary stimulus for behavioral and autonomic thermoregulation. We assessed whether the sensation of skin and core temperatures for the driving force of behavioral thermoregulation was modified by postural change from the supine (Sup) to sitting (Sit) during mild hyperthermia. Seventeen healthy young men underwent measurements of noticeable increase and decrease (±0.1 °C/s) of skin temperature (thresholds of warm and cold sensation on the skin, 6.25 cm2of area) at the forearm and chest and of the whole-body warm sensation in the Sup and Sit during normothermia (NT; esophageal temperature (Tes), ∼36.6 °C) and mild hyperthermia (HT; Tes, ∼37.2 °C; lower legs immersion in 42 °C of water). The threshold for cold sensation on the skin at chest was lower during HT than NT in the Sit (P < 0.05) but not in Sup, and at the forearm was lower during HT than NT in the Sup and further in Sit (both, P < 0.05), with interactive effects of temperature (NT vs. HT) × posture (Sup vs. Sit) (chest, P = 0.08; forearm, P < 0.05). The threshold for warm sensation on the skin at both sites remained unchanged with changes in body posture or temperature. The whole-body warm sensation was higher during HT than NT in both postures and higher in the Sit than Sup during both NT and HT (all, P < 0.05). Thus, thermal sensation during mild hyperthermia is modulated by postural change from supine to sitting to sense lesser cold on the skin and more whole-body warmth.
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Takeda
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.|Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Imai
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Akina
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Ota
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Nooshin
authors.initials: N
authors.lastname: Naghavi
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yamashina
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Hirasawa
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.|Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Hisayo
authors.initials: H
authors.lastname: Yokoyama
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.|Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Miyagawa
authors.affiliation: Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan. okazaki@sports.osaka-cu.ac.jp.|Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan. okazaki@sports.osaka-cu.ac.jp.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Okazaki
mesh_terms: D000328:Adult; D001794:Blood Pressure; D001833:Body Temperature Regulation / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply; D012881:Skin Temperature; D013546:Sweating; D013696:Temperature; D013697:Thermosensing / Q000502:physiology*; D055815:Young Adult
keywords: Behavioral thermoregulation; Central blood volume; Non-thermal factors; Passive heating