title: Wearing a cooling jacket during exercise reduces thermal strain and improves endurance exercise performance in a warm environment.
abstract: The aim of the present study was to investigate the effect of wearing a cooling jacket on thermoregulatory responses and endurance exercise performance in a warm environment. Nine untrained male subjects cycled for 60 minutes at 60% Vo(2)max (Ex1) and then immediately exercised to exhaustion at 80% Vo(2)max (Ex2) in 32.0 +/- 0.2 degrees C and 70-80% relative humidity. Four separate conditions were set during exercise: no water intake (NW), water intake (W), wearing a cooling jacket (C) and the combination of C and W (C+W). Rectal temperatures (T(re)) before Ex1 were not different between the 4 conditions, whereas at the end of Ex1 T(re) of C+W was significantly lower than the C and W (p < 0.05). Mean skin temperature (T(sk)) was significantly lower in C and C+W than the NW and W during Ex1. Heart rate of C and C+W were significantly lower than the NW and W, and rating of perceived exertion (RPE) in C+W was lower than in the other conditions. Exercise time to exhaustion was significantly longer in C+W than in the other conditions (NW < W, C < C+W; p < 0.05), whereas T(re) at exhaustion was not different. Our results indicate that the combination of wearing a cooling jacket and water intake enhances exercise endurance performance in a warm environment because of a widened temperature margin before the critical limiting temperature is reached and also because of decreased thermoregulatory and cardiovascular strain.
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima, Japan. hasehiro@hiroshima-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hasegawa
authors.forename: Tadashi
authors.initials: T
authors.lastname: Takatori
authors.forename: Takashi
authors.initials: T
authors.lastname: Komura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamasaki
mesh_terms: D000328:Adult; D001833:Body Temperature Regulation / Q000502:physiology*; D003080:Cold Temperature; D004326:Drinking / Q000502:physiology; D016552:Ergometry; D006339:Heart Rate / Q000502:physiology; D006361:Heating; D006801:Humans; D006813:Humidity; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D012881:Skin Temperature / Q000502:physiology; D013546:Sweating / Q000502:physiology