It's hot, very hot. You are used to doing your running, rowing or biking workout in the afternoon or after work, but guess what? If you stick to that regimen, you could be coping with some serious hydration and core-temperature issues.
The easiest way around the problem is to plan a day ahead for an early morning workout, when the temperatures are in the 60s and 70s and dehydration (sweating) is happening at the normal rate, says Andy Baxter of Baxter Fitness Solutions in Medford and Ashland.
If you parent in the mornings or can't schedule it at that time, remember that things cool off after 6:30 or 7 in the evening and there's still plenty of light, says Joe Lusa, coach of the Ashland Rowing Club.
Or you could take a break from the outdoors, go in an air-conditioned gym and get your aerobic drill on a treadmill or elliptical trainer — or swim a bunch of laps, he adds.
It's called cross-training — it will be good for you and you can get back to your regular passion when it cools down in a few days.
In hot weather, train smart and think about doing an intense half-hour (instead of an hour) of exercise, and keep your MAHR (maximum aerobic heart rate) at 180 minus your age, says Baxter.
"The big caution in hot weather is dehydration. You have to be careful not to replace a lot of water without electrolytes in it. Calcium, sodium and potassium are the big three and they're in all the sports drinks," says Baxter, noting that you should avoid electrolyte-replacement drinks with sugar or corn syrup as these "sit heavy in the gut."It's a given in the fitness world that it is good for you to exercise, drink lots of water and cut down on salt, but in hot weather this can be a recipe for an affliction called hyponatremia, an electrolyte imbalance caused by drinking in and sweating out too much water so you don't have enough sodium in your body. Signals are cramping, nausea, vomiting, headache and malaise.
"When it's over 100 degrees, a workout can be pretty devastating on the body because you lose fluids through perspiration and things start shutting down," says Lusa. "You get flushed and have heavy perspiration, which means you're overheated — or no perspirations, which is a sign of low core temperature and heat stroke. You should stop the workout."
The signs of heat stroke are similar — disorientation, passing out and nausea. If you don't rest and rehydrate, it's dangerous enough that it could lead to death, Baxter says.
You should be careful in outdoor workouts such as cycling or rowing, where you're moving with the wind in your face and you might not notice how much you're sweating, says Baxter.
Heat is something you can build tolerance to in as little as a week. Fit people tolerate heat better, sweat more, sweat at lower temperatures and have decreased salt depletion, says personal trainer Carol Lee Rogers of Ashland.
But the front line is always hydration, she notes. Inadequate hydration cuts sweat rate and increases the chance of "heat injuries."
During your workout, focus not on replacing salt or carbs, but water, Rogers adds. Wear clothes made from fabrics such as polypropylene that wick sweat to the surface for evaporation. And don't wait until you feel thirsty to drink because when you feel it, you've already sweated out too much fluid and are clinically dehydrated.