title: Effects of brief leg cooling after moderate exercise on cardiorespiratory responses to subsequent exercise in the heat.
abstract: We investigated the effects of brief leg cooling after moderate exercise on the cardiorespiratory responses to subsequent exercise in the heat. Following 40 min of ergometer cycling [65% peak oxygen uptake (VO(2peak))] at 35 degrees C (Ex. 1), seven male subjects [21.9 (1.1) years of age; 170.9 (1.9) cm height; 66.0 (2.0) kg body mass; 46.7 (2.0) ml kg(-1) min(-1) VO(2peak)] immersed their legs in 35 degrees C (control condition, CONT) or 20 degrees C (cooling condition, COOL) water for 5 min and then repeated the cycling (as before, but for 10 min) (Ex. 2). Just before Ex. 2, esophageal temperature ( T(es)) was lower in COOL than in CONT [36.9 (0.2) vs 37.5 (0.1) degrees C] ( P<0.01), as also were both mean skin temperature [33.9 (0.2) vs 35.2 (0.2) degrees C] ( P<0.01), and heart rate (HR) [93.2 (6.0) vs 102.7 (4.9) beats min(-1)] ( P<0.05). During Ex. 2, no differences between CONT and COOL were observed in oxygen uptake, arterial blood pressure, blood lactate concentration, or ratings of perceived exertion; however, T(es), skin temperature, and HR were lower in COOL than in CONT. Further, during the first 5 min of Ex. 2, minute ventilation was significantly lower in COOL than in CONT [50.3 (2.0) vs 53.4 (2.6) l min(-1)] ( P<0.01). These results suggest that brief leg cooling during the recovery period may be effective at reducing thermal and cardiorespiratory strain during subsequent exercise in the heat.
authors.affiliation: Institute of Health and Sports Science, University of Tsukuba, 305-8574, Tsukuba City, Ibaraki, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Hayashi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Honda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ogawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Wada
authors.forename: Narihiko
authors.initials: N
authors.lastname: Kondo
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishiyasu
mesh_terms: D000328:Adult; D001831:Body Temperature / Q000502:physiology; D003080:Cold Temperature; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006439:Hemodynamics / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D007866:Leg / Q000502:physiology*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology*; D012881:Skin Temperature / Q000502:physiology
chemical_list: D019344:Lactic Acid