Heat exhaustion, heat stroke, and dehydration are serious medical problems. Knowing how to diagnose and treat them is important. More importantly, know how to avoid them:

• Drink lots of water.
• Avoid exertion in the heat of the day.

During the summer, the lower desert areas may reach temperatures of 115 degrees Fahrenheit. Don't underestimate the consequences of running out of water. Each hiker needs as much as two gallons of water every day. When temperatures exceed 100 degrees Fahrenheit a person can survive only a day or two without water.

Even when water is plentiful and the weather is moderate, dehydration can still be a problem. Even a slight loss of body fluid decreases your mental and physical abilities, and increases your susceptibility to heat-related medical problems.

Always drink the water you have. Conserving water is a poor plan and leads to dehydration. Your body can lose significant amounts of moisture without sweating and without you becoming thirsty. Drink more water than required to quench your thirst.

Many sport drinks replace electrolytes, which are essential to processing the water you drink.

If stranded or low on water in hot weather, conserve your sweat. Rest in the shade during the day to reduce your water needs. Travel during the morning and evening, or at night, when the air is cooler.

Medications and Drugs

Some medications, such as certain antidepressants, antihistamines, thyroid hormones, and especially "recreational drugs," increase your chances for heat stroke. Know before you go.

Danger Signs

Know the danger signs of heat exhaustion and heat stroke:

• Excessive sweating or no sweating.
• Confusion or disorientation.
• Dizziness or headache.
• Dark colored urine or no urine.

Recovery

To cool a heat victim:

• Get them into the shade.
• Pour water over their head and fan them (but don't completely immerse them in water).