Happy Herbivore Blog

April 21, 2013

Staying Hydrated: How Much Water Do We Need to Drink?

After sharing my recipe for a homemade sports drink on Friday, a few people emailed asking how much water we need to drink every day.

"I was wondering your take on the saying, 'Drink 8 glasses of water a day" and what the benefits are :)??? Thanks :)"



Before getting into specifics, I think we can all agree that hydration is important — and the more water we drink, the better (although drinking too much water can cause hyponatremia which is rare, but can be fatal).

If it's hot outside, you're being active, or you're at a high altitude, it's especially important to make sure you're drinking enough water to prevent dehydration.

As for how much water you should drink, there is no easy one-size-fits-all answer, and the standard "8 glasses of water a day" isn't necessarily accurate. (It's popular because it's easy to remember).

The Institute of Medicine determined the adequate fluid intake for a man living in a temperate climate (with no medical issues) was 3 liters (about 13 cups) of liquid per day. For a woman living in a temperate climate (with no medical issues) it was 2.2 liters (about 9 cups).

My "rule" has always been the color of my urine. The clearer, the better. If my urine is very yellow or dark, I know I need to go drink some water.

The Mayo Clinic agrees, "If you drink enough fluid so that you rarely feel thirsty and produce 6.3 cups or more of colorless or light yellow urine a day, your fluid intake is probably accurate."

While it's a great idea to keep water within reach at all times, I wouldn't go to extremes trying to ensure you're drinking 8 cups of water a day. Remember: you take in fluid from food, too.

Here's the good news! If you're eating a whole foods plant-based diet, you're consuming a lot of water through the foods you eat. Most plant foods have a very high water content. For example, many fruits and vegetables, such as watermelon and tomatoes, are 90 percent or more water by weight. Other fluids, like herbal tea, also count.

Staying Safely Hydrated:

Exercise. If you exercise or engage in any activity that makes you sweat, you need to drink extra water to compensate for the loss — 1.5 to 2.5 cups of water should suffice for short bouts of exercise, but intense exercise (exercise that lasts for more than an hour), requires much more fluid. The Mayo Clinic also recommends drinking fluids that contain sodium to help replace the sodium lost in sweat and reduce the chances of hyponatremia. (Add some salt to my sports drink recipe above).

Environment. Hot and humid weather can make you sweat, thereby requiring you to replenish fluids. Heated indoor air can also cause your skin to lose moisture during the cold, winter months. Further, altitudes greater than 8,200 feet may trigger increased urination and more rapid breathing, which also deplete your fluid reserves.

Health. Fever, vomiting or diarrhea (as unpleasant as they are to begin with) can rapidly deplete your fluid reserves, so it's important to hydrate when you're sick. Other health conditions such as kidney disease, may also require you to limit (or increase) your daily fluid intake. Additionally, women who are expecting or breast-feeding will also need to take in more liquid. The Institute of Medicine recommends that pregnant women drink 10 cups of fluids per day; 13 cups for women who are breast-feeding.

Lastly, if you find water a little too boring on it's own — try our suggestions for jazzing up water.

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