Mike Carlson, NASM-CPT
Water is everywhere. It makes up 71 percent of planet earth and about 73 percent of each of us. Approximately 92 percent of Hollywood starlets are photographed carrying a bottle of designer H2O. With all these liquid assets it's hard to believe we still don't drink enough water.
"I think most people are in a state of mild dehydration," says exercise physiologist Eric Sternlicht, PhD, an assistant professor of kinesiology at Occidental College in Southern California. Sternlicht makes the point that even thirst is not a sufficient indicator of when the body needs water.
"The thirst mechanism kicks in when you are about 2 percent dehydrated," Sternlicht says. "That already means a 10 percent loss of performance."
Water serves the body in a myriad of forms, from digestion to temperature control to even bowel regularity. Playing so many roles, it is no wonder that people can tap their water stores in a few short hours. Active people, especially when exercising in hot weather, can dehydrate even faster, making themselves prone to energy dips, sluggish thinking, a slowed metabolism and increased risk of heat-related illnesses.
Water vs. Sports Drinks
Water isn't the only way to replenish fluids. Teas, juices and sports drinks will also rehydrate you. (Caffeinated and alcoholic beverages tend to have a slight diuretic affect, and thus should not be counted as part of your daily intake.) However, when it comes to exercising for a purpose, such as improving endurance or losing fat, the choice between water and a bottle of greenish-hued sports drink can make a major difference.
"Stick with water when you are trying to cut the calories and are concerned about your physique," says Greg Werner, MS, CSCS, ACSM-HFI, the director of strength and conditioning at James Madison University in Harrisonburg, Virginia.
For men and women looking to drop a little body fat, and who engage in moderate intensity training sessions, the calories in a sports beverage may be unwelcome. After all, if you spend 30 minutes burning 250 calories on a stationary bike you don't want to spend the next 30 seconds slurping 225 calories. In that case, water is your best choice. But if you train for performance, or for periods longer than an hour, you can benefit from a sports drink during and immediately after a workout.
"It has been shown that if you consume small amounts of sugar during a workout, it will prolong the intensity of the workout," says Werner. "I encourage my athletes to drink a little before a workout, a little during and as much as they need afterwards. And later that night, just drink water. At night, their glycogen [muscle energy] stores are saturated and if they drink more sugar it will just turn to fat."
Sternlicht and Werner both agree that one advantage of a sports drink is the taste. "All the research has shown that people will drink more if there is a little taste to it," says Werner.
Too Much of a Good Thing?
Last year a sensational headline made its way through the mainstream press: "Too much water can kill you!" Yes, even the most basic element of our existence was now under fire. Does that mean we should be pouring our Evian down the drain? Not a chance, says Sternlicht.
"That study was about hyponatremia, a condition that only effects marathoners and ultra-endurance athletes," he says. Hyponatremia occurs when massive amounts of salt and other electrolytes are lost through profuse sweating and only water (sans minerals) is used to rehydrate. While it can be deadly it is exceedingly rare. "I have not run across one case of hyponatremia," affirms Werner.
With the warm weather of summer upon us, water intake becomes even more important. So, whether it is a $6 bottle of designer water from a French aquifer or a quick stop at your gym's fountain, never miss an opportunity to rehydrate.