Symptoms of Trouble
The most common symptoms of heat illness are nausea, vomiting, headache, weakness, or an altered mental state (confused, raving, aggressive, rambling incoherently). Body temperature can spike up to 105 degrees or more (110 to 114 degrees is not unknown). If the sweating mechanism shuts down as it did in Albert's case, over time the body loses all hope of cooling itself and the brain and other organs begin to "cook." Heat stroke is the term for this latter condition and can result in death.
But it's not that simple. "I usually don't want to say heat exhaustion is a first stage of heat stroke or that it can go from one to the other," Roberts says. "They are two different things. You can get exercise exhaustion in the heat, but it's usually from the exercise not the heat."
Giving it a name is not that important. "You may suddenly get tired, sick, headachy, thirsty, or faint," sums up McCauley.
Hydration Not the Whole Answer
The most common piece of advice about exercising in the heat is drink, drink, drink -- water, not caffeine-loaded sodas or beer. Roberts says you can get heat exhaustion even if you are hydrated, though. He recommends determining your sweat rate instead and replacing that, without overdoing it.
To determine your sweat rate, weigh yourself nude before your workout, then towel down and weigh again. The difference in ounces is the fluid you lost. "Replace that, not twice that," Roberts says. "Too much fluid can be bad, too."
McCauley, on the other hand, recommends drinking a quart before running or exercising outside, and a quart after. "Drink even if you are not thirsty," she says.
What about salt tablets? "They got a bad rep because they were thought to contribute to high blood pressure," Roberts explains. However, he still recommends augmenting with salt. "You know when you first exercise and the sweat drips in your eyes and it stings?" he asks. "Well, after two or three weeks of exercising in the heat, your salt level will go down. So I recommend eating a few more salty foods, pretzels, potato chips, or salt your food."