Tip 1:Exercise in the Early Morning or Late Afternoon
"The best times to exercise in the heat are early in the morning or late in the evening. "You definitely do not want to exercise in the afternoon because you're going to lose a lot more fluid that way," says Osborn. "Swimming is probably the best activity. I see a lot of people running in the afternoon and that's probably the worst thing you could do.
Osborn also says, "exercising early in the morning is probably the best. It's what I would recommend, as early as you can, to avoid the heat of the day.
Tip 2: Drink Plenty of Water
"I'd also try to get eight glasses of eight ounces of water a day. You should probably try to do more than that and sip on it throughout the day. As you're exercising, you want to do the same thing. You don't want to chug a lot of water. You can make yourself sick doing that, so you want to take small sips of water during your exercise bout, maybe no more than two sips."
Tip 3: Sunscreen, Sunscreen, Sunscreen
"You definitely need sunscreen if you're going to avoid skin cancer. SPF 30 at least. I wouldn't use anything lower. Avoid working out between times of 10 and 2 and 3 o'clock in the afternoon because that is when the sun is hottest and highest. You want to avoid those UV rays.