It may be less than you think
Adding fruit to water may make it more palatable.
By Larissa Zimberoff
Drinking eight glasses of water a day seems like one of life’s immutable laws. So it may sound surprising, but hydrating adequately doesn’t mean measuring and downing water all day long.
While eight glasses a day can be a useful guide, it’s not a mandate, because individual fluid needs vary. And what goes toward our bodies’ hydration needs isn’t just water. "Various foods and beverages help get your fluid intake," says Sotiria Everett, RD, clinical assistant professor at Stony Brook Medicine in Stony Brook, N.Y.
However, you should still pay attention to proper hydration, especially if you’re older. The thirst mechanism that tells us to drink can diminish with age. In warmer weather, heat stroke and other heat-related conditions are a risk.
But chronic dehydration can have consequences too, namely "speeding up the aging process via increased cellular stress," says Asher Rosinger, PhD, director of the Water, Health, and Nutrition Lab at Penn State College of Health and Human Development in University Park. Here’s what to eat and drink to make staying hydrated less chore-like.
Water is great because it’s calorie- and sugar-free (add a squeeze of fruit or a splash of juice for flavor). But seltzer, milk, and fruit juice are also healthy ways to get your fluids. Even coffee and tea count. Caffeine is a diuretic—meaning it increases urine production—but the water in these drinks more than compensates for its effects. Just watch how much sugar you add. Hydrating with sugary drinks isn’t a good idea—not because they don’t contribute fluids, but because they contain empty calories and they’re unhealthful in other ways.
You also don’t need to be sipping drinks and powders that claim to be "ultra-hydrating." Typically, these products have electrolytes, such as sodium and potassium, which the body loses through sweating. But they may also have other ingredients you don’t want, such as sugar and artificial flavors, says Everett. Athletes may benefit from them, but "for individuals who are participating in moderate exercise, water is good," she says.
Nearly everything we eat has some water in it, and that water does help us stay hydrated. For example, Greek yogurt is 84 percent water by weight, canned tuna is 79 percent, and cooked pasta is 62 percent. Soups and smoothies also supply fluids. But fruits and vegetables are the best water replacers. For example, watermelon is 91 percent water. Here’s how many ounces of water you get in a serving of seven seasonal fruits and vegetables.
• Watermelon: 1 small wedge = 7 oz. water
• Cantaloupe: 1 cup = 5 oz. water
• Peach: 1 large = 5 oz. water
• Cucumber: 1 cup = 4 oz. water
• Tomato: 1 large = 4 oz. water
• Zucchini: 1 cup = 4 oz. water
• Corn: 1 ear = 3 oz. water
Are You Getting Enough Water?
Pay attention to your body: Symptoms of low hydration are fatigue, wooziness, headaches, and cramps. "Thirst, urine, and weight are some ways to assess hydration," Everett says. Dark urine, for instance, could indicate underhydration, she says. Weighing yourself before and after exercise can help you determine how much fluid is lost. Everett says to drink 16 to 24 ounces of fluid for every pound you’ve lost after exercise.
Editor’s Note: A version of this article also appeared in the July 2023 issue of Consumer Reports On Health.
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