Table 5 Hydration practices for each included study

Arngrïmsson et al., 2004 [24]

Pre-test: instructed to drink water and other non-caffeinated beverages liberally

During the warm-up: water ad libitum. Tap temperature. Amount was recorded and repeated for the second condition.

Not reported/performed during exercise

Booth et al., 1997 [42]

During exercise trial: water ad libitum

Cotter et al., 2001 [25]

Pre-test: instructed to drink at least 15 ml/kg BM 2 to 3 h before arrival at laboratory

During the warm-up: water ad libitum after warm-up and before exercise trial

Not reported/performed during exercise

Duffield et al., 2010 [41]

Pre-test: 500 ml water 60 min before arrival at the laboratory

Not reported/performed during exercise

Gonzalez-Alonso et al., 1999 [40]

Pre-test: 200 to 300 ml with breakfast

Not reported/performed during exercise

Hasegawa et al., 2006 [43]

Pre-test: 500 ml 2 h before the trial

Immersion: no fluid ingestion

Immersion + water ingestion: water (14 to 16°C) every 5 min during exercise equal to volume sweat loss in sweat test performed at a prior visit to laboratory

Water ingestion: water (14 to 16°C) every 5 min during exercise equal to volume sweat loss in sweat test performed at a prior visit to laboratory

Control: no fluid ingestion

Ihsan et al., 2010 [16]

Pre-test: adequate hydration was strongly encouraged before testing

Pre-cooling: 6.8 g/kg BM ice slurry in 150 to 200 g aliquots in intervals of 8 to 10 minutes over a period of 30 minutes (1.4 ± 1.1°C)

Control: 6.8 g/kg BM tap water slurry in 150 to 200 g aliquots in intervals of 8 to 10 minutes over a period of 30 minutes (26.8 ± 1.3°C)

During exercise trial: 100 ml water (26.8 ± 1.3°C) at four intervals

Kay et al., 1999 [28]

During exercise trial: water ad libitum

Quod et al., 2008 [27]

Pre-test: 250 ml sport drink diluted to half the manufacturer's recommended strength

During exercise trial: 250 ml sport drink diluted to half the manufacturer's recommended strength

Ross et al., 2011 [17]

Pre-test: water (4°C) ad libitum throughout heat stabilization and warm-up

Pre-cooling: 14 g/kg BM ice slurry in two 7 g/kg BM boluses 15 minutes apart

Control: water (4°C) ad libitum

During exercise trial: subjects were provided with 350 ml of a 6% carbohydrate-electrolyte drink at 12.5 and 37.5 km to consume ad libitum for the next km (drinks left out in heat temperature to simulate race conditions)

Siegel et al., 2010 [18]

Pre-test: instructed to drink at least 2 l fluid the day before the trial, and 400 ml during the meal consumed before the trial

Pre-cooling: 7.5 g/kg BM ice slurry (-1°C) with 5% carbohydrate in 1.25 g/kg BM aliquots every 5 minutes over a period of 30 minutes

Control: 7.5 g/kg BM water (4°C) with 5% carbohydrate in 1.25 g/kg BM aliquots every 5 minutes over a period of 30 minutes

Not reported/performed during exercise

Siegel et al., 2012 [19]

Pre-test: instructed to drink at least 2 l fluid the day before the trial, and 400 ml during the meal consumed before the trial

Pre-cooling: 7.5 g/kg BM ice slurry (-1°C) with 5% carbohydrate in 1.25 g/kg BM aliquots every 5 minutes over a period of 30 minutes

Immersion: 7.5 g/kg BM water (37°C) with 5% carbohydrate in 1.25 g/kg BM aliquots every 5 minutes over a period of 30 minutes

Control: 7.5 g/kg BM water (37°C) with 5% carbohydrate in 1.25 g/kg BM aliquots every 5 minutes over a period of 30 minutes

Not reported/performed during exercise

Ückert and Joch, 2007 [26]

Pre-test: avoid fluid for 3 h before start of test

Not reported/performed during exercise