Be smart about staying hydrated

By now, even the most casual recreational athlete has heard the admonitions to stay hydrated during exercise, especially in the summer.

Yet, some confusion persists because aspects of the research and official recommendations remain, pardon the pun, fluid.

Substances once deemed strictly verboten when it came to hydrating for exercise - caffeine in moderation, for one - now aren't considered quite so detrimental. And fancy carbohydrate- and electrolyte-rich sports drinks, once thought the height of replenishment, in many cases now are usurped by plain old water.

Then there was what some exercise physiologists call the Great Hyponatremia Scare of 2002, when a Boston Marathon participant died from overhydrating. (This dilutes sodium levels in the body.) The death prompted some overly hasty about-faces among some experts on the "drink before you're thirsty" dictum.

Caveats and exceptions abound, of course.

But we've sorted through the contradictions in recommendations from organizations such as the federal Centers for Disease Control and Prevention, the American College of Sports Medicine and USA Track & Field to come up with generally accepted guidelines that runners, cyclists, soccer players and others can follow to stay cool and hydrated during workouts this summer.

Workouts one hour or less

Water, not sports drinks, is sufficient to replace fluids.

Drink 16 to 20 ounces two to three hours before a ride, run or competition.

Drink another 12 to 16 ounces 15 minutes before exercising.

During exercise, drink 5 ounces every 10 to 15 minutes.

Workouts longer than one hour

Consume sports drinks - same quantity as above - that contain 6 percent to 8 percent carbohydrate concentration. Make certain the drinks contain electrolytes to replace lost sodium and potassium.

On longer workouts, take in one gram of sodium per hour. Add sodium to sports drinks, if needed.

Consider chilling or freezing water or sports drinks on long runs or bike rides to avoid the fluid becoming too warm.

Drink 16 to 20 ounces of water or a sports drink just after exercise.

Measuring sweat and dehydration levels

Weight should remain constant pre- and post-exercise. Disrobe and step on a scale before the workout, note weight and repeat the process afterward. If you weigh less, you needed to drink more. If you weigh more, cut down on drinking.

After a long workout, if there are white, chalky streaks on your clothes or face, you are a salty sweater and need more sodium during exercise.

Take the urine-color test: Clear means fully hydrated, light yellow is fine, apple-juice color or darker means varying levels of dehydration.

Other hot-weather tips

Wear loose-fitting, sweat-wicking clothing that will allow air to circulate but protect you from the sun. Avoid cotton.

Wear a hat and sunscreen to protect from direct sunlight.

Refrain from drinking sodas and energy drinks. They contain carbohydrates (sugar) and are not absorbed well. They also contain high levels of caffeine, which act as diuretics. Research has found, though, that three to six milligrams of caffeine before a workout does not impede heat tolerance.