Hydrate or die. It’s an extreme view of things, but it’s the truth. The human body is made up of 55 to 60 percent water, and we need it to lubricate our joints, deliver nutrients to cells, keep our organs functioning properly, prevent infection and improve cognition and sleep.
A 2012 study published in the Journal of the American College of Nutrition showed that just two percent dehydration impairs performance in tasks requiring attention, psychomotor, and memory skills. And when we exercise, we dehydrate more quickly, because sweating and heavier, faster breathing means more fluid is evaporated away. Along with that water goes electrolytes, which regulate blood pressure and muscle contraction, and are essential to keeping our delicate internal ecosystem in balance.
Long-term dehydration can lead to chronic back pain, headaches, depression, high blood pressure, digestive disorders, obesity, premature aging, kidney problems, and possibly even diabetes and heart disease. Signs and symptoms of dehydration in the short term; however, can include the obvious thirst, though it is very common for adults to be dehydrated without feeling thirsty; nutritionists often say if you feel thirsty, you’re already too late. Other signs of dehydration include dry mouth or lips, dizziness, a rapid heartbeat, nausea, cramps, decreased performance, decreased urine output, and darker urine color. Urine is a reliable indicator of hydration levels, as a well-hydrated person’s urine is almost colorless.
But how to make sure you’re properly hydrated? Non-athletes can divide their body weight in pounds in half to get their recommended number of ounces of water per day; that is, a 180-pound man should drink 90 ounces, while a 140-pound woman should drink 70. However, those who exercise regularly require more water to stay adequately hydrated.
Jenn Gargiulo, RDN, CSSD, recommends men consume 128 ounces and women consume 100 ounces per day, as a baseline. “As far as hydration during workouts, it’s all relative to the temperature, both hot and cold, the altitude, and the intensity and duration of the workout,” Gargiulo says. According to Gargiulo, those working out at a moderate pace for under an hour don’t need to consume water during a workout unless they want to, but everyone should enter a workout properly hydrated. She recommends an ounce of water per ten pounds of bodyweight in the hour leading up to a workout; a 180-pound man should consume 18 ounces, while a 140-pound woman should consume 14. If exercising for longer than an hour, 10 ounces per 20 minutes of workout activity is recommended. Athletes should also adjust their hydration plans based on their sweat rate.
“Your sweat rate can be determined by weighing yourself before and after exercise to get an idea of how much fluid is lost,” Gargiulo says. “Following exercise, athletes should consume 16 to 24 ounces of fluid for every pound lost during exercise for proper rehydration.”
It’s also important to remember that being properly hydrated doesn’t just mean you’ve had enough water. It also means your body’s electrolyte mineral levels are properly balanced because sodium, potassium, magnesium, and calcium are all lost through sweat. When working out for extended periods in extreme heat or cold, or for anyone who sweats a lot, Gargiulo recommends supplementing water with electrolytes, like those found in an intra-workout or multivitamin.
It is; however, important to be realistic about your activity level; many electrolyte replenishment supplements are high in calories and skipping them in favor of regular water can put 200 calories back into your daily food bank. There are also many zero or lower-calorie options to choose from. And if it’s simply flavor you’re after because regular water doesn’t excite your taste buds, Gargiulo suggests naturally flavored water, unsweetened herbal teas, or a powdered multivitamin.