FLUID FLUENCY
Everything you need to know about hydrating in the heat
Running during these scorching summer months can leave you parched as a lizard in the Mojave Desert. And yes, you probably know you need to drink a lot of liquid during these times, but you may not realize just how vital it is. Taking in too little fluid can be disastrous for your running and your health. Drink the right amount of the right beverages, and you'll feel great and run fast.
Here's a look at how water works to keep your body running smoothly, with some tips on when, how much and what kinds of fluids to drink. Plus, I've provided a rundown of many of the sports beverages on the market.
You're All Wet
On average, the human body is more than 50 percent water. Runners and other endurance athletes average around 60 percent. This equals about 120 soda cans' worth of water in a 160-pound runner! A runner's watery physique results from physiological adaptations brought about by running. For one, running builds lean muscle tissue and reduces body fat; lean tissue contains more water than fat tissue does. (Fat tissue contains the least water of all body tissues, even less than bones.)
Another reason for your waterlogged state is your expanded blood volume. This occurs as you become physically fit and serves to improve oxygen and nutrient delivery to working muscles. The extra blood also helps remove wastes produced by muscles during exercise.
Sweat It
During running, muscles generate heat - lots of it. A typical 5-mile run burns about 500 calories, and 70 percent of this heat must exit the body to keep muscle tissue from literally cooking. The body stays cool by producing sweat, the evaporation of which rids your body of unwanted heat - roughly 600 calories of heat for every quart of sweat that evaporates. And during an hour of running, you can easily lose more than 2 quarts of sweat.
How much you sweat depends upon several factors. Warm weather and high humidity both increase sweat production. And the faster you run, the more heat you generate, so the more you sweat. Sweat rate is also influenced by your fitness level: the sweat glands in a fit body enlarge and increase in number, so you sweat more. All these bodily adjustments create more efficient cooling while you run.
