Although there has been a fair amount of research on drinking cold fluids to reduce hyperthermia many of the methods have been inconsistent. One recent study, published by the Journal of the International Society of Sports Nutrition, reviewed the impact of drinking cold water on body temperature during cardio exercise, and then performance on subsequent resistance exercises like the bench press. The study found that drinking very cold water in intervals during cardio helped substantially to keep core body temperatures closer to normal than room temperature water. There was only a small improvement in subsequent resistance exercise performance, but this was likely due to the fact the body temperature extremes in this particular study weren’t as divergent from normal as in some other recent studies.
Although the resistance exercise wasn’t importantly impacted in this study, the more important factor was elucidated. Cold water ingestion is effective at helping athletes maintain an ideal body temperature for exercise. On a hot day or when exercising intensely, be sure to keep some cold water on hand to stay hydrated, and to prevent hyperthermia from bringing your performance down.