Summertime is usually packed with outdoor activities in sweltering summer weather. Extreme heat and the sun can cause several types of heat injuries or illnesses and occasionally even death. The Center for Disease Control and Prevention (CDC) credits extreme heat conditions with about 400 deaths per year in the United States.

To protect your health during the summer, remember to keep cool and use good judgment.

Heat-related illnesses such as heat exhaustion, heat cramps and heat rashes are easy to treat at home, while a heat stroke requires professional medical attention. Here are some things to keep in mind:

Heat rash is a skin irritation caused by excessive sweating during hot, humid weather. Heat rash looks like a red cluster of pimples or small blisters. It normally occurs on the neck and upper chest, in the groin, under the breasts and in elbow creases. To treat it move to a cooler, less humid environment and keep the affected area dry.

Heat cramps may happen if you don’t drink enough fluids when exercising. Symptoms include painful muscle cramps of the limbs, stomach and back, as well as heavy sweating and extreme thirst. Stop all activity, sit quietly in a cool place and drink clear juice or a sports beverage. Do not return to strenuous activity for a few hours after the cramps subside, because further exertion may lead to heat exhaustion or heat stroke. Seek medical attention for heat cramps if they do not subside in 1 hour.

Heat exhaustion is triggered by excessive sweating and inadequate fluid replacement, making the body unable to supply blood to the brain, skin and muscles. Symptoms include dizziness, profuse sweating, nausea, vomiting, muscle cramps, rapid breathing and fainting. Treat with rest and cool non-alcoholic beverages in an air-conditioned place. If heat exhaustion is untreated, it may progress to heat stroke.

Heat stroke occurs when the body’s sweat mechanism shuts down, making skin hot and dry and depleting the body of fluids. Symptoms include a throbbing headache, delirium, weakness, nausea, vomiting, flushed dry skin, disorientation and confusion. Heat stroke is a medical emergency that demands immediate treatment by a medical professional.

Asthma sufferers should monitor their breathing levels throughout the day during heat waves and high humidity. High temperatures make air pollution worse and humidity increases the pollen in the air. Take medications as directed by a doctor to prevent a trip to the emergency room. When symptoms of asthma are present it is best to stay indoors in the air conditioning.

When going out in the heat here are tips to help prevent heat illness or injury:

Wear sunscreen. Be protected form the sun and sunburn by putting on sunscreen of SPF 15 or higher.

Drink plenty of fluids. Increase fluid intake, regardless of activity level and don’t wait until the feeling of thirst occurs to drink. During heavy exercise in a hot environment, drink at least two glasses of cool fluids each hour.

Replace salt and minerals. Heavy sweating removes necessary salt and minerals from the body. If you exercise drink plenty of fluids.

Wear cool clothes. Wear as little clothing as possible when at home. Choose lightweight, light-colored, loose-fitting clothing.

Stay cool. During extreme heat or humidity, stay indoors and, if possible, stay in an air-conditioned place. Go to a public place or building if you have no air conditioning—even a few hours spent in air conditioning can help the body stay cooler when you go back into the heat. If you must be outdoors try to limit your outdoor activity to morning and evening hours.

For more information about beating the heat and staying safe, visit www.bt.cdc.gov⁄disasters⁄extremeheat⁄heat_guide.asp.

(Kelley is deputy assistant secretary of defense for clinical and program policy and acting chief medical officer, TRICARE Management Activity.)