Received April 21, 2006
Revised May 11, 2006
Accepted after revision June 14, 2006
Human, Environmental & Exercise [250]
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Drink temperature influences fluid intake and endurance capacity during exercise in a hot, dry environment
Toby Mundel 1*,
Jenny King 1,
Esther Collacott 1,
David A Jones 2
1 The University of Birmingham
2 The University of Birmingham, Manchester Metropolitan University
* To whom correspondence should be addressed. E-mail: t.mundel{at}bham.ac.uk.
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Abstract |
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The effect of different drink temperatures on the perception of exertion and exercise endurance has not been extensively investigated. Consequently, the purpose of the current study was to examine the effect of drink temperature on fluid intake and endurance during cycling in the heat. Eight healthy, non-acclimated males (26 ± 7 years, VO2max: 54 ± 5 ml kg-1 min-1; mean ± SD) cycled to exhaustion at 34°C and at 65% of their peak aerobic power, consuming a drink at either 19°C (CON) or 4°C (COLD). Six of the 8 subjects cycled for longest during COLD, with exhaustion occurring at 62 ± 4 min, compared to 55 ± 4 min for CON (p < 0.05; mean ± SE). Subjects consumed significantly more fluid during COLD compared to CON (1.3 ± 0.3 l h-1 compared to 1.0 ± 0.2 l h-1; p < 0.05). Heart rate tended to be lower by ~5 beats min-1 during COLD, and rectal temperature during the second half of exercise was ~0.25°C lower during the COLD trial, however, these were not significant (p = 0.08, p = 0.07, respectively). No differences were observed between trials for ventilation, concentrations of prolactin, glucose and lactate or perceived exertion. It is concluded that a drink at 4°C during exercise in the heat enhances fluid consumption and improves endurance by acting as a heat sink, attenuating the rise in body temperature and therefore reducing the effects of heat stress.
Key Words:
Exercise, Hyperthermia, Thermoregulation
