Are there any special considerations for exercisers? "How much additional fluid you need when you exercise depends almost entirely on how much you sweat," Cheuvront says. "Typical sweat rates for people exercising are on the order of half to one liter per hour," he says. "For competitive athletes who exercise at high intensity, it is not unusual to see sweat rates as high as one-and-a-half liters per hour. Sweat rates can vary even for the same person under different conditions—running slow or fast, in hot weather or cool weather."
The best way to calculate your sweat rate is to weigh yourself without clothes before and after your workout. Then, for each pound lost, you'll need 16 ounces of fluid to fully compensate. "Most people, if left to their own devices, will naturally replace the sweat they lose during exercise over the next 24 hours," Cheuvront says. Determining if you're well hydrated is simple; nearly clear first morning urine is a good way to gauge if you're getting enough fluid.
What about sports drinks? Sports drinks contain electrolytes that are helpful to replace when you exercise for an hour or longer or in hot weather, Anding says. But if you exercise for less than an hour a day, the meals you eat afterward will naturally restore lost fluids and electrolytes.
Sports drinks have other helpful benefits. They provide carbohydrates for energy during intense exercise. "Also, since sports drinks are flavored, many people drink more than they would if they just drank water," Anding says. Achieve a similar effect by adding a splash of fruit juice to your water.
Should I drink fluids during exercise? You only need to consume fluids during exercise if you're likely to become dehydrated (that doesn't happen until you lose more than two percent of your total body weight, or about three pounds). If you routinely lose more than three pounds during exercise, sipping fluids during your workout can help prevent dehydration. The fluid you choose is up to you.
Does bottled water offer advantages over tap? What about fortified waters? Bottled water is popular—more than half of us drink it. It's portable, so you can drink it on the go. And it offers consistent taste. The taste of tap water, on the other hand, can vary from place to place. Tap water is usually treated with fluoride, which helps maintain strong teeth and bones. Fortified waters confer the same advantages as other bottled waters, and contain additional vitamins and nutrients. They're fine in moderation, though "you can obtain plenty of vitamins and minerals from eating a balanced diet," Anding says.
