Table 6.
Characteristics of research studies evaluating cognitive performance
| Citation | Participants | Dh protocol; ambient temperature; duration | Total REC (min) | Dh trial BM loss (%) | Fluid type | Fluid assimilation time (min) | Fluid intake (L∙kg BM lost−1) |
Cognitive domains assessed | Ambient temperature; RH; airflow | Cognitive domains significantly affected by fluid intake (Hedges’ g) |
|---|---|---|---|---|---|---|---|---|---|---|
| Cian et al. (2001a) [55] | 7 M, unacclimated, endurance trained | EX (V); 25 °C; 120 min | Testing at 140 and 240 min | 2.7 | CHO + electrolyte | 80/180 | 1.00 | Memory Perceptive discrimination Psychomotor function/processing speed Mood |
NS | ↑ Memory 2-h post-Dh |
| Cian et al. (2001b) [55] | 7 M, unacclimated, endurance trained | HT | Testing at 140 and 240 min | 2.6 | CHO + electrolyte | 80/180 | 1.00 | Memory Perceptive discrimination Psychomotor function/processing speed Mood |
NS | ↑ Memory 2-h post-Dh ↓ Fatigue |
| Grego et al. (2004) [48] | 8 M, endurance trained cyclists | EX (V); 20–21 °C; 180 min | 5 | 4.1 | Water | 185 | 0.73 | Perceptual discrimination Memory/processing speed |
NS | No effect |
| Serwah et al. (2006a) [68] | 8 M | EX (V); 31 °C; 90 min | 3 | 1.7 | Water | 9 | 1.00 | Psychomotor function/processing speed | NS | No effect |
| Serwah et al. (2006b) [68] | 8 M | EX (V); 31 °C; 90 min | 3 | 1.7 | Water | 90 | 0.50 | Psychomotor function/processing speed | NS | No effect |
| Edwards et al. (2007b) [58] | 11 M, moderately active soccer players | EX; 19–25 °C; 90 min | 0 | 2.4 | Water | 90 | 0.80 | Visual scanning/processing speed | NS | No effect |
| Adam et al. (2008a) [56] | 8 (6 M), physically active soldiers | HT | 120 | 3.0 | NS | 300 | NS | Psychomotor function/processing speed Psychomotor function Perceptive discrimination Visual scanning/vigilance |
20 °C; 50%; 1 m/s | No effect |
| Adam et al. (2008b) [56] | 8 (6 M), physically active soldiers | HT | 120 | 3.0 | NS | 300 | NS | Psychomotor function/processing speed Psychomotor function Perceptive discrimination Visual scanning/vigilance |
2 °C; 50%; 2.2 m/s | No effect |
| D’Anci et al. (2009a) [73] | 16 M, university athletes | EX; 60 min | NS | 2.0 | Water | 60 | NS | Memory Psychomotor function/processing speed Arithmetic/processing speed Visual scanning/vigilance Spatial processing Mood |
NS | ↑ Psychomotor function/processing speed ↓ Anger, fatigue, depression, tension and confusion; ↑ vigour |
| D’Anci et al. (2009b) [73] | 13 (0 M), university athletes | EX; 60–75 min | NS | 1.7 | Water | 60-75 | NS | Memory Psychomotor function/processing speed Arithmetic/processing speed Visual scanning/vigilance Spatial processing Mood |
NS | ↑ Psychomotor function/processing speed ↓ Anger, fatigue, depression, tension and confusion; ↑ vigour |
| Ganio et al. (2011) [69] | 24 M, physically fit | EX; 28 °C; 40 min | 20 | 1.6 | Water | 60 | NS | Psychomotor function/processing speed Visual scanning/vigilance Memory/processing speed Learning/memory Logical reasoning/processing speed Mood |
23 °C | ↑ Psychomotor function/processing speed and memory/processing speed ↓ Fatigue and tension |
| Ely et al. (2012b) [67] | 32 M, unacclimated | EX; 50 °C; 3 h W/R | 90 | 4.1 | NaCl + water | 270 | 1.00 | Psychomotor function/processing speed Memory/processing speed Logical reasoning/processing speed Mood |
Testing at 10, 20, 30 and 40 °C | No effect |
| Wilson et al. (2014) [60] | 8 M, licenced jockeys | EX; 20 °C; 45 min | 0 | 1.8 | Water | ~35 | 1.00 | Response inhibition | NS | No effect |
| Wittbrodt et al. (2015a) [70] | 12 M, recreationally active | EX (V); 32 °C; 50 min | NS | 1.5 | Water | >50 | 1.00 | Psychomotor function/processing speed Memory Perceptive discrimination Visual scanning/processing speed |
32 °C; 65% | No effect |
| Wittbrodt et al. (2015b) [70] | 12 M, recreationally active | EX (V); 32 °C; 50 min | NS | 1.5 | Water | >50 | 0.80 | Psychomotor function/processing speed Memory Perceptive discrimination Visual scanning/processing speed |
32 °C; 65% | No effect |
Exercise intensity is described as high (H), vigorous (V) or moderate (M), in accordance with classifications outlined by Norton et al. [86]. Values are Hedges’ g effect sizes
CHO carbohydrate, Dh dehydration, EX exercise, HT heat, NS not specified, Total REC time from completing the dehydration protocol to commencing the subsequent task, W/R work rest cycle