Don't eat too much: A large meal, especially large amounts of protein or fat, forces your body to shunt resources to your digestive system. By forcing your body to focus on digestion, you are placing additional strain on your body's resources that should be used to regulate your body's temperature. Obviously if you are running long, you will need some food for energy, but keep your food consumption smaller and perhaps more frequent. Eating smaller amounts, but more often, can help you maintain your energy level without overly stressing your body.
Wear lighter clothing: When the temperature is warmer than you're used to, strip down to fewer clothes, and don't wear cotton. Wear clothes made of wicking material to help take the moisture away from your skin. Also, don't run shirtless. A light, wicking shirt can actually keep some moisture near your skin and help your body remain cool.
Stay near your home base: If you're on vacation and going for your regular runs, try to stay within a few miles of your home base or hotel. Run loops if necessary. Staying near your home base allows you to stop or get help fairly quickly if you're having difficulties or become dehydrated. If you're in a race, there should be people on the course able to help if you run into trouble.
Listen to your body: You know what is normal for you and when something is not right. At the first sign of muscle weakness or dehydration, stop running. Walk home, call a friend for a ride or take a cab if you suspect your body is not handling the heat well. There is no point in possibly hurting your body so that you have to stop running for weeks or months. Be smart and listen to your body. It knows best.
Know the signs of heat stroke: The usual signs of heat stroke include a throbbing headache, dizziness, lack of sweating, red, hot and dry skin, muscle weakness or cramps, nausea or vomiting, a rapid heartbeat, rapid and shallow breathing, confusion or disorientation and also fainting. If you experience any of these symptoms, stop running and seek help immediately. Never keep running through any of these symptoms, as heat stroke can lead to a host of dangerous scenarios including death.
Many people in colder climates, like Michigan, train during the winter months for races down South. (The Disney World races are especially popular.) There's no reason to worry about training in the cold for a warmer-weather race as long as on race day, you pay attention to your body and be smart about helping it stay cool. So whether you're running a warm-weather race or looking forward to your vacation runs, use these tips to stay safe and enjoy your run.race.