We’ve all heard the rule that we should drink eight, 8-ounce glasses of water each day to stay properly hydrated and healthy. But where did this rule come from? What is the science and research behind the recommendation? Do you need to drink more water if you work out a lot? And what about the foods, like soup and grapefruit, that have a lot of water in them? Do they count towards your daily water-total?
A new commentary in the British Medical Journal, where a doctor called the recommendation to drink six to eight glasses of water a day, “thoroughly debunked nonsense,” is causing many to question what had been considered hydration-law. To clear this whole water-recommendation thing up, we talked with some experts about hydration to get the real deal on how much you really need to drink.
Do I Need to Drink Eight Glasses of Water a Day?
Basically, there is no one-size-fits-all approach when it comes to optimal hydration, says Dr. Josh Wagner, owner of The Life House on Manhattan’s Upper East Side, where he practices chiropractic and sports medicine.
“Eight cups of water per day is the classic recommendation for keeping hydrated, but how could, say, a 105-pound woman need to consume the same amount of water as a 240-pound man?” Dr. Wagner asks. “I usually advise my patients to drink at least half their body weight in ounces of water per day, and to add even more water if they tend to enjoy caffeinated beverages or alcohol or if they have other health concerns, such as diabetes. You’ve heard it before, but water makes up such a large percentage of our bodies and is one of the most important parts of a healthy lifestyle.”
Do Food and Other Beverages Count?
In a nutshell, yes! While it’s not ideal to count caffeinated beverages because they’re a diuretic, your foods and other non-water drinks can count towards your daily water goal, says Charla McMillian, a certified strength and conditioning specialist and operator of FitBoot. Although water is the ideal choice because it’s calorie-free, broth and non-caffeinated teas and coffee, fruits and vegetables, soups and sports drinks, among other water heavy-foods count.
There’s even some research that suggests that caffeinated beverages like coffee and tea can improve hydration — if you’re used to drinking them, she says.
“There is evidence that those accustomed to consuming caffeine may not actually suffer significantly less hydration from it than those perhaps just starting with it as they look to hydrate under strenuous exercise,” McMillian says.
Do Athletes and Exercisers Need to Drink More?
Simply put, people who are more active and work out, do need to drink more says Katie McCreless, Arizona State University personal trainer and wellness expert. The most important factor is that exercisers and athletes of all levels begin their workouts hydrated from the beginning, and then continue to sip throughout and after.
“If a person is exercising a lot or at a competitive level, it is important that they are well hydrated prior to engaging in physical activity, which means that they will need to pay attention the day before,” McCreless says.
McCreless tells clients to follow the American College of Sports Medicine’s hydration recommendations to weigh yourself before and after physical activity. Then, she has clients drink one pint of water for every pound of body weight lost. “Your body won’t perform as well during the activity or recover as well post-exercise if you aren’t well hydrated,” she says.
However, it’s important to not go overboard with the water. Having too much water in the system at one time can flood a persons cells and cause a serious and possibly life-threatening condition called hyponatremia, also known as overhydration.
A Fool-Proof Way to Make Sure You’re Properly Hydrated
One easy way to monitor your hydration? Pay attention when you go to the restroom, says Dr. Dale Peterson, author of Building Health by Design: Adding Life to Your Years and Years to Your Life.
“For many years I have recommended a simple strategy for monitoring the body’s hydration status,” Dr. Peterson says. “Simply drink enough water to keep the urine pale and require emptying of the bladder at two- to three-hour intervals. If urination is infrequent and the urine becomes darker, the body is saying that it needs more water.”
Easy enough, right?