A cold glass of water makes a very refreshing drink on a hot day or after a sweat session, but what if one glass is not enough? What if I need five glasses of water or a 20 oz bottle? Will I suffer from water intoxication or hyponatremia?
According to WebMD, individuals who are young and healthy will generally not develop hyponatremia unless they drink multiple liters of water at once. Our kidneys can only expel about half a liter of water within an hour. A half of a liter is equivalent to about 17 fluid ounces. So, if I were to consume a 20 oz bottle of water in one sitting, I will likely not put myself at risk of developing hyponatremia. However, if I drank four 20 oz bottles of water in one sitting, the chance of developing hyponatremia becomes much more likely.
When you drink an enormous amount of water at one time (think multiple gallons), the excess water may cause your sodium or salt levels to reduce drastically which may result in the fatal condition called hyponatremia. The sodium levels are regulated so that the fluids around the cells remain balanced. When the sodium levels are too low, the fluids move from the blood to inside the cells which causes the cells to swell. Swelling inside of the brain is a serious problem that requires swift medical attention and can result in seizures or a coma. If you are exercising for two hours or more, you should consider replenishing with a sports drink in conjunction with plain water; search this website for the post called “Recovery Basics: Cool Down and Replenish” for more information.
According to M.D. Alert, each year more athletes suffer from hyponatremia than dehydration. John Henry Dreyfuss advises that approximately 13-15% of endurance athletes have experienced hyponatremia. In addition, he states that sodium supplementation does not appear to affect the occurrence of hyponatremia. As a result, it appears that the most effective advice that coaches can provide is to tell endurance athletes to drink only when thirsty.
Bottom Line: Too much of anything can be harmful as the body seems to thrive in a balanced state; water is no exception. Drink water when thirsty and avoid consuming gallons of water as a weight management technique. Otherwise, you may end up putting yourself at risk for hyponatremia.