People are often reminded from doctors and social media to drink plenty of fluids in order to remain in good health and physical shape. The effects of not drinking enough water can be seen quite often, especially amongst athletes. But can too much water actually be harmful?
It turns out that drinking too much water can cause severe conditions and even be fatal. It is sometimes referred to as water intoxication. Drinking excessive amounts of water can have a dilutive effect on the salt levels in the blood. There is a constant concentration of sodium in the blood, in order to keep all the processes in the body functioning normally. When big amounts of water get consumed, sodium level falls. When the concentration is too low, it causes blood vessels to become permeable and excess water leaks in other tissue. This condition is called hyponatremia.
Hyponatremia can cause severe damage to organs, especially the brain. Brain is soft tissue and it is contained in the skull. In case of hyponatremia, excess water goes from blood vessels to brain cells, causing swelling of the tissue. In mild cases symptoms can be: confusion, nausea, vomiting and headache. If the swelling continues, seizures can develop. Worst case scenario is for brain to swell so much, that it no longer has space in the skull. In this case syndrome called brain stem herniation occurs, which is a fatal condition.
Death from using excessive amount of water is very rare amongst athletes. Still, sports medicine specialists encounter these cases from time to time. For example, in 2014, a 17 year old football player consumed too much water during practice and later died. It has also become a trend to use fluid based detoxification diets. Using a diet based only on fluids, without supervision from a doctor can be very dangerous. Another risk group for hyponatremia is older people, that have reduced kidney function and who use diuretics.
There are some measures that can help to reduce the risk of water intoxication. One of those are taking enough salt (sodium) during physical activities. For example, for marathon runners it is better to drink sports drinks that contain enough sodium and also other electrolytes. A good way to measure how much water a person needs while exercising is to weigh yourself before physical activities, and afterwards weighting yourself again. The weight difference gives an idea how much fluid has been lost during a certain period of time. It has also been observed, that slower runners are more predisposed to water intoxication, because they take time to stop and drink.
The amount of fluid that should be consumed by average person with normal daily activities is 3 liters for men and 2.2 liters for women. This is an approximate value that can differ from person’s age, weight, height and medical conditions. It can also vary depending on the type and amount of physical activities. This amount also includes the fluid taken from food and other drinks, not only water.
