The Best Ways to Stay Hydrated All Day Long

It's a no-brainer that you need plenty of water, especially after soaking through your sports bra during a workout. But you may not be guzzling enough. In fact, on average, Americans drink a little more than four glasses a day, which is a drop in the bucket. Shortchanging yourself can affect your workout, your weight — even your brainpower. Why? Virtually every system in the body relies on H2O, says Lawrence Armstrong, Ph.D., a professor of exercise and environmental physiology at the Human Performance Laboratory at the University of Connecticut. Water protects and hydrates our organs, transports nutrients to our cells and helps us stay energized and mentally sharp. It also balances the level of electrolytes—minerals such as sodium and potassium—in your body to keep your muscles functioning properly.

However, exactly how much you should drink is a slippery issue. The Institute of Medicine gives a ballpark goal of 91 ounces a day for women, which includes the water you get from food. And then there's the standard eight-glasses-a-day rule. But neither of these edicts is right for everyone, experts say. That's because you may have different water needs than the woman on the treadmill next to you. Not only that, your own water requirements change one day to the next depending on how hard you've exercised, if you've gained or lost weight, what your hormones are up to and what you're doing at any given moment. "We have a very dynamic and complex water system in our bodies, which changes every hour of the day," Armstrong explains. "That's why there is no absolute amount."

The best way to stay hydrated starts with determining how much water you need for the day ahead is to weigh yourself in the morning, he says. To find your happy H2O weight, drink what you feel is an adequate amount (until your thirst is satisfied and your pee is a light color; it becomes dark when you're dehydrated) every day for one week. Each morning, weigh yourself on a digital scale first thing after peeing. Take the average of the three most similar numbers—that's your baseline weight when you're properly hydrated. From then on, step on the scale every morning, and "if you're a pound lighter, drink an extra 16 ounces that day," Armstrong says.

What You Need to Know About Water and Hydration

1. You don't need to guzzle a gallon of H2O during your exercise session.

It seems like the best way to stay hydrated during a sweaty gym session, but when you work out at a moderate intensity for less than an hour, you only need to drink enough to satisfy your thirst. If you go an hour or more or you're exercising in hot conditions, weigh yourself before and after you work out and sip an extra 16 ounces of water per pound lost.

2. Water can give your workout a boost.

Plain H2O will hydrate you just fine during a typical sweat session so that you can get the most out of your routine. If you prefer the taste of coconut water, though, go for it. It contains some carbs, which can help give you a lift. If you're deficient in certain nutrients, vitamins may help improve your performance. In that case, try vitamin-enhanced water.

3. Stash your water in the freezer before you exercise.

Cold H2O is better for your workout than water at room temperature. In a British study, people who had a very cold drink before and during sweaty cycling sessions were able to keep going significantly longer than those who drank their beverage at warmer temps, probably because the icy sips kept their core body temperatures lower.

4. Drinking water can help you lose weight.

Sipping before meals helped dieters consume 90 calories less at each meal, according to a recent study. Again, cold water may be a better choice; research has found that you burn slightly more calories after drinking it, probably because your body expends energy to heat the water up.

5. H2O is good for your skin.

"The hyaluronic acid in your skin absorbs some of the water you drink," says Doris Day, MD, a dermatologist in New York City. "This gives it some of its elasticity and vibrancy." But there's no need to chug an ocean of the stuff. "Once the hyaluronic acid has absorbed all it can, you'll simply pee the rest out," Dr. Day says. The best rule of thumb: If your skin doesn't bounce back right away when you pinch it, drink up.

6. Your Starbucks habit is not dehydrating you.

Turns out, cutting back on coffee isn't the best way to stay hydrated. Caffeine is a mild diuretic, but it doesn't lead to dehydration, according to Armstrong's research. You can even count caffeinated drinks toward your total fluid intake, says Lauren Slayton, RD, the author of The Little Book of Thin and the founder of Foodtrainers in New York City. Eight ounces of coffee equals roughly four ounces of water.

7. It is possible to drink too much water.

This can be a serious problem for endurance athletes, especially women, who are smaller than men and so have less water in their bodies, says Timothy Noakes, M.D., the director of research in exercise science and sports medicine in the Department of Human Biology at the University of Cape Town. Drinking large amounts of water can cause a condition called hyponatremia, in which the sodium levels in the blood drop too low and brain cells and tissue become bloated, leading to nausea, confusion, seizures, coma, and even death. But the condition is rare. The average gymgoer, or even a triathlete who drinks only to quench thirst, is highly unlikely to consume more water than their body can handle, Dr. Noakes says.

The Best Way to Stay Hydrated with Water

• Infuse your H20 for added flavor and hydration. Put fruit slices, such as lemon, lime, and orange, in a pitcher of water and refrigerate. (

The Best Way to Stay Hydrated with Food

These foods are a tasty and easy way of upping your H2O intake without hitting the bottle.

• 1 cup chicken noodle soup = 8 oz. (or one of these tasty bone-broth soups.)
• 1 cup cooked sliced zucchini = 6 oz.
• 1 medium apple = 6 oz.
• 1 cup cantaloupe cubes = 5 oz.
• 1 cup watermelon balls = 5 oz.
• 1 cup cherry tomatoes = 5 oz.
• 1 small navel orange = 4 oz.
• 10 medium baby carrots = 3 oz.
• 1 cup raw broccoli florets = 2 oz.