Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8650111 | Journal of Thermal Biology | 2018 | 5 Pages |
Abstract
The effects of pre cooling on endurance performance are widely known. In contrast, the approach of cooling during endurance exercise in combination with pre-exercise cooling has been poorly understood. The purpose of the present study was to determine whether the effects of precooling and cooling during exercise enhance exercise performance compared to the ingestion of a thermo-neutral beverage (20â¯Â°C) or precooling alone in cycling performance. This was an experimental study using a randomised crossover design in which 7 cyclists underwent three trials comprising of 45â¯min steady state cycling (SS) at 70% VO2 max and a subsequent 10â¯km time trial (TT) in hot conditions (32â¯Â°C, 50% relative humidity). Rectal temperature (Tre), heat storage (HS), heart rate (HR), blood lactate concentration (BLA) and thermal sensation (TS) were measured. The intervention consisted of: (1) ingestion of thermo-neutral beverage before and during SS cycling (TN), (2) ingestion of ice slurry beverage and application of iced towels (precooling) prior to exercise, and then ingestion of thermo-neutral beverage during SS (PRE) and (3) precooling strategy as above plus ice slurry ingestion during SS cycling (PRE + MID). The intake of thermo-neutral or ice slurry beverage (14â¯g/kg) occurred over 30â¯min before and every 15â¯min during SS cycling. There was no significant difference in TT performance between all the conditions (P =0.72). However, PRE and PRE + MID caused a significant decrease in Tre (P < 0.05) from TN during exercise. Accordingly, both precooling and a combination of precooling and mid-cooling during exercise in hot conditions may be a practical and effective way of reducing core temperature. Future studies should investigate longer distance events and timing of ice slurry ingestion.
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Authors
Gaizka Mejuto, Samuel Chalmers, Stephanie Gilbert, David Bentley,