Before you head out for a sunny summer getaway, get familiar with the signs of heat-related illnesses. Once at your destination, build in time for your body to adjust to the climate.

If you're lounging by the water and taking only short walks, your risk of a heat illness is low. But if you're not in great shape and aren't used to the heat, beware of strenuous activities like hiking and biking.

Your body's cooling system could fail if you're in high temperatures and humidity for too long, sweating heavily, and not drinking the right fluids. Toss in a few fruity alcoholic beverages and you could be thrown for a loop.

Respect your fitness level. If you're out of shape, go slow, even for fun activities like kayaking. Take frequent breaks. Don't wait until you feel thirsty to drink bottled water. And don't forget the sunscreen.

Heat-related illnesses include:

• Heat cramps: painful muscle contractions, usually after exercising in the heat.
• Heat syncope: lightheadedness or fainting caused by high temperatures.
• Exercise-associated collapse: lightheadedness or fainting right after exercising.
• Heat exhaustion: body temperature as high as 104 Fahrenheit with cold, clammy skin, headache, weakness, nausea and vomiting.
• Heat stroke: the above symptoms plus a body temperature over 104 F; you may no longer be able to sweat to cool yourself.

Preventing heat-related illnesses:

• Give yourself time to acclimate to the heat.
• Avoid activities during the hottest part of the day -- exercise in the morning or evening, and in the shade.
• Wear light, loose clothes and a wide-brimmed hat.
• Stay hydrated, but don't overdo fluid intake.
• If you've been exercising for many hours in the heat, eat a salty snack or lightly salt your next meal to replace salt losses.

Know the signs of heat-related illnesses:

• Cramping.
• Confusion or irritability.
• Excessive sweating.
• Fatigue.
• Feeling dizzy, lightheaded, nauseous or weak.
• Headache.
• Increased heart rate and/or low blood pressure.
• Vision trouble.
• Vomiting.

Take immediate steps if you develop any of these symptoms. Get out of the heat, lower your body temperature with wet towels or sit in a tub filled with cold water, and rehydrate with water or a sports drink. And contact a physician if necessary.