Pre-cooling with intermittent ice ingestion lowers the core temperature in a hot environment as compared with the ingestion of a single bolus

• Published in: Journal of thermal biology 2016-07, Vol.59, p.13-17
• Main Authors: Naito, Takashi, Ogaki, Tetsuro
• Format: Article
• Language: English
• Subjects: Acclimatization; Adult; Body Temperature; Body Temperature Regulation; cold; Cold Temperature; Drinking; Eating; Hot Temperature; Humans; ice; Ice - analysis; ingestion; Male; males; relative humidity; sensation; specific gravity; temperature; Thermosensing; urine; Young Adult
• ISSN: 0306-4565; 1879-0992
• DOI: 10.1016/j.jtherbio.2016.04.006

The timing in which ice is ingested may be important for optimizing its success. However, the effects of differences in the timing of ice ingestion has not been studied in resting participants. Therefore, the purpose of this study was to investigate the effects of differences in the timing of ice ingestion on rectal temperature (Tre) and rating of perceptual sensation in a hot environment. Seven males ingested 1.25gkg−1 of crushed ice (ICE1.25: 0.5°C) or cold water (CON: 4°C) every 5min for 30min, or were given 7.5gkgBM−1 of crushed ice (ICE7.5) to consume for 30min in a hot environment (35°C, 30% relative humidity). The participants then remained at rest for 1h. As physiological indices, Tre, body mass and urine specific gravity were measured. Rating of thermal sensation was measured at 5-min intervals throughout the experiment. ICE1.25 continued to decrease Tre until approximately 50min, and resulted in a greater reduction in Tre (−0.56±0.20°C) than ICE7.5 (−0.41±0.14°C). Tre was reduced from 40 to 75min by ICE1.25, which is a significant reduction in comparison to ICE7.5 (p