Summer is officially in full swing. But don't let the increased heat and humidity bat you down!

"The very young, the elderly, especially those with chronic diseases, and those who work or exercise vigorously outdoors are especially at risk," said Christine Grant, New Jersey Department of Health and Human Services commissioner. "But anyone exposed to heat can develop heatstroke, heat exhaustion or other heat-related illnesses. And in the summer, more people than ever are participating in outdoor activities.

Heatstroke, the most serious of these illnesses, occurs when the body loses the ability to cool itself. Victims can go from being apparently normal to being extremely ill in a matter of minutes. They will have a high body temperature (106 degrees Fahrenheit or higher), very hot and dry skin, a rapid and strong pulse, and may be delirious or unconscious. People suffering heatstroke need immediate medical attention.

Heat exhaustion is a milder illness that may take several days of high temperatures to develop. It occurs when the body's water and salts lost through perspiration are not adequately replaced. Victims may have pale, clammy skin and be sweating profusely. They may feel tired and weak, dizzy, have a headache and sometimes cramps, but their body temperature is close to normal. Heat exhaustion can be severe enough to require hospitalization.

"There are a number of steps people can take to guard against these illnesses," Grant said. "One of the most important things to do is to drink plenty of fluids, even if you aren't thirsty. When the body is under stress from heat, you may need up to 50 percent more to drink than your thirst would indicate.

"But stay clear of drinks with alcohol or caffeine," Grant warned. "Such drinks can lead to dehydration."

Other advice for avoiding heat-related illness, the department said, includes:

• Spend a few hours in an air-conditioned place -- such as a shopping mall or the library -- to help cope with hot, humid weather.

• Check on elderly relatives and neighbors to see if they need help taking proper heat precautions, or if they need medical attention because of the heat. Be sure individuals who are bedridden or have mobility problems have adequate fluids within easy reach.

• If you are elderly or otherwise at risk, take advantage of any air-conditioned shelters that are set up during heat waves.

• Take care not to overdress children and to give them plenty of liquids to drink throughout the day. Children under age 5, particularly those under age 1, are especially sensitive to the effects of heat.

• Don't leave children, a frail elderly or disabled person, or pets in an enclosed car -- not even for a minute -- as temperatures can climb quickly to dangerous levels.

• If possible, reduce physical activity or reschedule it for cooler parts of the day. Wear loose and light-colored clothing. When in the sun, be sure to wear a hat or head covering.

• Check with your healthcare provider before taking salt tablets. Salt supplements are not necessary for the general public, although those who regularly work under very hot conditions should consider drinking fluids supplemented with the appropriate salts.

• Talk to your healthcare provider about any medicine or drugs you are taking. Certain medications, such as tranquilizers and drugs used to treat Parkinson's disease, can increase the risk of heat-related illness.