You should acclimate your body to increases in temperature gradually. Cut back on your regular routine and then gradually increase the amount of exercise you do over the next few weeks. It is not safe to exercise during extreme heat and/or humidity. Try to avoid the hottest part of the day, generally from 10 a.m. to 3 p.m.
Wear light colored, loose fitting, cotton clothing. Wear a hat and use sunscreen to protect you from sunburn. Be very aware of the dangers of dehydration. You should drink plenty of water before, during, and after exercise in warm weather. Your body can lose up to a quart of water an hour. It is possible to over-hydrate, so don’t overload your body on fluids. But you will need about one to two cups of fluid every 20 to 30 minutes of exercise, depending on the heat and your level of activity.
If you begin to feel weak, dizzy, or nauseous, you may have the first signs of heat exhaustion. You may also get a headache, notice that sweating stops, or feel overheated. At the first sign of any of these symptoms, stop exercising, move to a cooler location, and drink some water. If the symptoms persist, see a doctor immediately.