The truth about water – how much do we actually need?
The Truth About Water
Whenever you disregard your sense of thirst and strive to ingest several glasses of water a day just because you have been told that doing so is good for your health, you actually put unnecessary strain on your body in two major ways:
- Ingesting more water than you need can increase your total blood volume. And since your blood volume exists within a closed system (your circulatory system), needlessly increasing your blood volume on a regular basis puts unnecessary burden on your heart and blood vessels.
- Your kidneys must work overtime to filter excess water out of your circulatory system. Your kidneys are not the equivalent of a pair of plumbing pipes whereby the more water you flush through your kidneys, the cleaner they become; rather, the filtration system that exists in your kidneys is composed in part by a series of specialized capillary beds called glomeruli. Your glomeruli can get damaged by unnecessary wear and tear over time, and drowning your system with large amounts of water is one of many potential causes of said damage.
Putting unnecessary burden on your cardiovascular system and your kidneys by ingesting unnecessary water is a subtle process. For the average person, it is virtually impossible to know that this burden exists, as there are usually no obvious symptoms on a moment-to-moment basis. But make no mistake about it: this burden is real and can hurt your health over the long term.
Forcing your body to accept a large amount of water within a short period of time – say, an hour or two – as several contestants did during the “Hold Your Wee for a Wii” contest can be fatally dangerous to your health. Here’s why:
If you force large amounts of water into your system over a short period of time, your kidneys will struggle to eliminate enough water from your system to keep the overall amount at a safe level.
As your circulatory system becomes diluted with excess water, the concentration of electrolytes in your blood will drop relative to the concentration of electrolytes in your cells. In an effort to maintain an equal balance of electrolytes between your blood and your cells, water will seep into your cells from your blood, causing your cells to swell.
If this swelling occurs in your brain, you’ll experience increased intro-cranial pressure i.e. your brain will get squeezed because the flat bones that make up your skull don’t provide much give. Depending on how much water your drink in a short period of time, you could experience a wide variety of symptoms, ranging from a mild headache to impaired breathing. As occurred in the tragic water-drinking contest, it’s quite possible to die if you drink enough water in a short period of time.
This information is particularly important for parents to pass on to their children. Foolish drinking contests are not uncommon among high school and university students, especially while playing cards.
So how much water should you drink to best support your health?
The answer depends on your unique circumstances, including your diet, exercise habits, and environment.