Come summer and your television with ads reminding you about how you should drink a lot of water, take sufficient amount of glucose to keep yourself hydrated. The way they say it, it feels like even a small drop in hydration levels would massively affect your performance. And there is one particular myth that stands among all.
We need 8 glasses of water per day!
And why wouldn’t we fall for it? Drinking water just sounds perfect when we are tired or when we feel less energetic. Well, It isn’t. We have been falling for this myth for so long now that it totally sounds like reality.
What does science have to say?
Well, earlier this year sports scientists in Australia did an extraordinary experiment that had never been done before (British Journal of Sports Medicine, September 2013, Current hydration guidelines are erroneous: dehydration does not impair exercise performance in the heat, Wall BA).
This group wanted to find out what happened to performance after dehydration. So they took a group of cyclists and exercised them until they lost 3% of their total body weight in sweat.
Then their performance was assessed after rehydration with either 1) nothing, 2) enough water to bring them back to 2% dehydration or 3) after full rehydration.
So far nothing unusual, but the difference between this and almost every other study that’s ever been done on hydration was that the cyclists were blind to how much water they got. The fluid was given intravenously without them knowing the volume.
This is vital because we all, and especially athletes, have such an intimate psychological relationship with water consumption.
Remarkably, there was no performance difference between those that were fully rehydrated and those that got nothing. This study was part of a growing movement to “drink to thirst” which hopes to persuade athletes not to over hydrate with the potentially fatal consequence of diluting your sodium level, causing hyponatremia.
Does that mean water is not that important?
It surely is. It’s a short leap of logic to think that if a lack of water is bad for you then hydration must be good. It actually doesn’t work this way. Water serves many beneficial purposes like purifying, cleansing, washing through your organs and of course detoxifying. It surely improves your skin, helps you think, reduces your risk of kidney stones and turns your urine a lovely light, straw/champagne color rather than the fetid orange syrup you produce at the end of a long day where you haven’t had time to drink. The problem occurs when we talk about myths. Like we said about the previous research, there is no particular quantity of water that does us any good or bad.
How did we reach at 8 glasses of water figure anyway?
Well, the grain of truth is this – people in temperate climates who are not doing sustained physical exercise do need around six to eight cups per day but that can be contained in food, alcohol or caffeinated beverages. There is no evidence that adding the eight cups of water to everything else you drink will do you any good and it could do you harm (American Journal of Physiological – Regulatory, Integrative and Comparative Physiology, November 2002, Drink at least eight glasses of water a day. Really? Is there scientific evidence for “8×8”? Valtin H).
I am confused. What should I do then?
You don’t have to worry about anything. Your body will take care of it for you. If you drink too much you pee it out. If you drink too little you get thirsty and pee less. It’s all exquisitely well-controlled in the same way that your intake of oxygen is well-controlled. Just like you don’t breathe too fast to get high supplies of oxygen, you don’t actually need 8 glasses of water to boost your performance.