Excessive water consumption can dilute your the fluids so much that the sodium levels become life-threateningly low.
Owing to excessive water consumption, people may die of over-hydration, termed as Exercise-Associated Hyponatremia (EAH). In simple terms, it means that you have drank too much water and the excess has diluted your body fluids so much that the sodium levels have become life-threateningly low, causing cells to swell. That includes brain cells leading to loss of consciousness, seizures and even coma and death. For long-distance runners, this can be a particular hazard.
Water intoxication is always on the cards if you believe you have to ‘stay ahead of thirst’ by drinking excessive quantities of fluids. To do so is entirely un-physiological. Drinking more water than you need increases your total blood volume and also pressures you kidneys into working overtime so as to filter excess water out of your circulatory system.
While exercising, you should balance how much water you drink to how much you are sweating out.
All runners should know that over-consumption of fluids, whether it’s water or sports drinks, can be fatal. EAH due to excessive hydration has caused at least a dozen deaths worldwide and there have been more than 1,600 documented cases of it around the globe.
The International Marathon Medical Directors Association advocates ‘drinking to thirst’ and no more. That means 0.03 litres per kilogram. So, for a 100 kg person that’s a maximum of three litres. The average man is around 70 kgs which means not more than 2.1 litres of water consumption.