Table 4.

Participant characteristics for each included study

Authors, year and reference	Participant characteristics
Arngrïmsson et al., 2004 [24]	Competitive collegiate and club middle/long distance runners
	Age men: 23.4 (4.4) years
	Age women: 22.1 (2.2) years
	Height men: 178.6 (4.4) cm
	Height women: 167.7 (5.5) cm
	Body mass men: 67.7 (4.2) kg
	Body mass women: 55.9 (4.3) kg
	Body fat men: 7.3 (2.0) %
	Body fat women: 17.8 (3.3) %
	Best 5 km run time men: 15.5 (0.8) min
	Best 5 km run time women: 17.9 (1.1) min
	VO2max men: 4.50 (0.31) l/min
	VO2max women: 3.24 (0.25) l/min
	Heat acclimatized
Booth et al., 1997 [42]a	Competitive runners from a local athletic club
	Age: 26.7 (1.7) years
	Height: 169.7 (4.0) cm
	Weight: 65.96 (2.87) kg
	Sum of eight skinfolds: 62.5 (9.7) mm
	Body surface area: 1.75 (0.06) m2
	Body fat: 15.8 (1.2) %
	HRmax: 189.5 (2.8) beats/min
	VO2peak: 63.1 (0.1) ml/kg/min
	Non-heat acclimatized
Cotter et al., 2001 [25]	Habitually active, but were of lower average aerobic fitness than subjects used in previous studies on the effects of pre-cooling
	Age: 32.4 (3.6) years
	Height: 175.6 (6.9) cm
	Body mass: 80.9 (10.5) kg
	Body surface area: 1.96 (0.15) m2
	VO2peak: 51 (8) ml/min/kg
	Non-heat acclimatized
Duffield et al., 2010 [41]	Moderate to well trained cyclists of club and regional standard who trained multiple times a week, competing in regional competitions
	Age: 24.8 (3.3) years
	Height: 178.3 (8.0) cm
	Body mass: 76.1 (2.7) kg
	Sum of seven skinfolds: 54.4 (10.9) mm
	Lactate threshold: 221 (42) W
	Non-heat acclimatized
Gonzalez-Alonso et al., 1999 [40]*	Endurance trained
	Age: 28 (3) years
	Height: 187 (6) cm
	Body mass: 77.9 (6.4) kg
	HRmax: 200 (9) beats/min
	VO2peak: 5.13 (0.30) l/min
	Non-heat acclimatized
Hasegawa et al., 2006 [43]*	Untrained
	Age: 21.8 (0.8) years
	Height: 1.72 (0.02) cm
	Body mass: 61.7 (2.1) kg
	Body fat: 15.1 (1.1) %
	VO2max: 48.5 (1.5) ml/kg/min
	Non-heat acclimatized
Ihsan et al., 2010 [16]	Endurance trained regularly competing in cycling or triathlon, cycling more than four sessions and > 150 km/week
	Age: 27.7 (3.1) years
	Height: 176.7 (5.8) cm
	Body mass: 81.38 (9.09) kg
	Non-heat acclimatized
Kay et al., 1999 [28]*	Moderately to well-trained and undertook bicycle riding, training and competition on a regular basis
	Age: 23.7 (2.1) years
	Height: 182 (3) cm
	Body mass: 76.1 (4.0) kg
	Sum of four skinfolds: 28.4 (2.3) mm
	Body surface area: 1.97 (0.06) m2
	HRmax: 184 (3) beats/min
	VO2peak: 4.91 (0.25) l/min
	Non-heat acclimatized
Quod et al., 2008 [27]	Well trained male cyclists with 6 (5) years of experience
	Age: 28 (4) years
	Height: 182 (2) cm
	Body mass: 75.1 (3.2) kg
	Sum of seven skinfolds: 50 (11) mm
	VO2peak: 71.4 (3.2) ml/kg/min
	Maximum aerobic power: 384 (23) W
	Non-heat acclimatized
Ross et al., 2011 [17]	Well trained A-grade cyclists aged 18 to 35 years
	Age: 33 (5.1) years
	Body mass: 72.1 (5.5) kg
	Maximum aerobic power: 449 (26) W
	VO2peak: 71.6 (6.1) ml/kg/min
	Heat acclimatized
Siegel et al., 2010 [18]	Moderately active, participating in recreational sport
	Age: 28 (6) years
	Height: 178.9 (6.3) cm
	Body mass: 79.9 (11.2) kg
	Sum of nine skinfolds: 92.8 (41.4) mm
	VO2peak: 56.4 (4.7) ml/kg/min
	Non-heat acclimatized
Siegel et al., 2012 [19]	Moderately active, were partaking in recreational sport
	Age: 26 (4) years
	Height: 179.9 (6.7) cm
	Body mass: 78.1 (5.9) kg
	Sum of nine skinfolds: 87.3 (22.5) mm
	VO2peak: 54.2 (2.5) ml/kg/min
	Non-heat acclimatized
Ückert and Joch, 2007 [26]	Regularly practiced types of sport with high endurance and strength components at a high level for example, soccer, athletics
	Age: 25.6 (3.5) years
	Height: 183.4 (7.6) cm
	Weight: 77.9 (9.5) kg
	Non-heat acclimatized

All values are mean (± SD).

^aValues in brackets are ± (SE).

HR = heart rate; VO₂max = maximal aerobic capacity; VO₂peak = peak oxygen uptake.