title: Lower thermal sensation in normothermic and mildly hyperthermic older adults.
abstract: OBJECTIVE
  It is important to know how thermal sensation is affected by normal aging under conditions that elevate core body temperature for the prevention of heat-related illness in older people. We assessed whether thermal sensation under conditions of normothermia (NT) and mild hyperthermia (HT) is lowered in older adults.
  
  
  METHODS
  Seventeen younger (23 ±  3 years) and 12 older (71 ±  3 years) healthy men underwent measurements of the cold and warmth detection thresholds ( ± 0.1 °C/s) of their chest and forearm skin, and whole body warmth perception under NT (esophageal temperature, T es, ~36.5 °C) and HT (T es, ~37.3 °C; lower legs immersed in 42 °C water) conditions.
  
  
  RESULTS
  Warmth detection threshold at the forearm was increased in older compared with younger participants under both NT (P = 0.006) and HT (P = 0.004) conditions. In contrast, cold detection threshold at the forearm was decreased in older compared with younger participants under NT (P = 0.001) but not HT (P = 0.16). Mild hyperthermia decreased cold detection threshold at forearm in younger participants (P = 0.001) only. There were no effects of age and condition on warmth and cold detection thresholds at chest. Whole body warmth perception increased during HT compared with NT in both groups (both, P < 0.001), and older participants had lower values than the younger group under NT (P = 0.001) and HT (P = 0.051).
  
  
  CONCLUSIONS
  Skin warmth detection thresholds at forearm and whole body warmth perception under NT and HT and skin cold detection thresholds at forearm under NT deteriorated with aging.
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, Osaka, 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, Osaka, 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, Osaka, 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, Osaka, Japan. okazaki@sports.osaka-cu.ac.jp.
authors.forename: Kazunobu
authors.identifier: http://orcid.org/0000-0003-1482-5516
authors.initials: K
authors.lastname: Okazaki
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D003080:Cold Temperature; D005542:Forearm / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D012684:Sensory Thresholds / Q000502:physiology; D012867:Skin / Q000503:physiopathology; D013697:Thermosensing / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Passive heating; Thermal sensation; Thermoregulation