Drink Cold Water to Improve Performance

It’s warming up out there and will be, for a while at least, great fun to train in this weather.  Keeping water cold is a challenge when you are out on the road for a while, but the Camelbak Big Chill works well.  The one problem is that it’s so cold and refreshing that I find myself chugging it, and then running out. Boo!  Anyway, it got me thinking about a correlation between my performance and drinking cold water and I started researching the link between hyperthermia (when your body temperature gets too high) and its effects on athletic performance.

Our bodies are efficient in cooling themselves through sweat.  However, in high humidity situations, the high water vapor content in the air means that the sweat produced by your body cannot evaporate into the air to release the heat you are producing.  So, the sweat drips off your body and doesn’t cool you, down.

Unfortunately, the human body is designed to function optimally within a small range of body temperatures. This range of safety and effectiveness may be higher in fit athletes, who may also be capable of temporarily and voluntarily over-riding discomfort from hyperthermia. However, in general, the cooler you can keep the body during exercise, the better your performance.

The most practical way to keep yourself cool is to then cool from the inside out. This can be done by drinking cold fluids.

A UK study by Lee et al. (1) looked at the possibility of rapidly cooling individuals prior to exercise by simply drinking cold fluids

The basic experimental plan:
– 8 males cycled moderately in a hot and humid environment to voluntary exhaustion.

– Pre-exercise, subjects drank 300 mL of either cold or body temperature water, followed by 100 mL of that drink each 10 min during exercise.

And the results?
– The cold drink was able to pre-cool subjects by 0.5oC.
– Exercise time at the fixed pace to the point of voluntary exhaustion was much longer with the cold drink (63.8 min) than with the warm drink (52.0 min).
– Heart rate and skin temperature was lower in the initial half of exercise with cold drink consumption, while overall sweat rate was less in the cold drink condition.
– Thermal sensations and ratings of perceived exertion were lower with the cold drink condition.

In summary, performance improvements may be achieved very simply by making sure that you’re adequately hydrated to begin with, and furthermore by ingesting a small amount of cold water or crushed ice before or during training or competing in the heat.

1.  Lee JK, Shirreffs SM and Maughan RJ. Cold drink ingestion improves exercise endurance capacity in the heat. Med.Sci.Sports Exerc. 40: 9: 1637-1644, 2008.

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