The dangerous effects of unusually high temperatures on the human body fall into three basic types: Heat Cramps, Heat Exhaustion, and Heat Stroke. The heat may come from the sun or in industrial settings such as open-hearth furnaces in steel mills, multiple ovens in bakeries, boiler rooms, mines, and some factories, or it may result from house fires or wildfires which affect firefighters and residents alike. Construction and road crews, farmers, ranchers, and other outdoor workers are at risk from the sun's heat, as well as runners, bikers, hikers, and other outdoor sports enthusiasts.
Heat Cramps are muscle spasms caused by the loss of salt and potassium through heavy perspiration. Often the lost water will have been replaced, but the necessary minerals -potassium and sodium - have not. These cramps may affect the legs, arms, or stomach. They may occur while the person is still engaged in the strenuous activity that produces the sweating - such as athletes who collapse with cramps on the football field or basketball floor - or they may suddenly occur later during the night or when he or she is relaxing at home. Although these cramps can be quite painful and temporarily debilitating, they do not usually result in permanent damage. Treat with a gentle massage of the affected muscle, manipulating the limb (bending or rotating it), and trying to stand on cramping legs. To prevent cramps, drink electrolyte solutions (sports drinks) during the day - along with plain water - and eat more potassium-rich foods such as bananas, orange juice, avocado, nuts and seeds, dried apricots, prunes, dates and raisins, baked potatoes, and dark chocolate.
Heat Exhaustion is more serious than cramping - the body's internal cooling system becomes overworked, but hasn't completely shut down. Heat exhaustion occurs when you don't drink enough fluids to replace that which is lost. This is especially easy to do in hot, dry conditions. Dry heat can cause the sweat to evaporate from your skin's surface quickly, so you may not be aware of how much you're perspiring. The surface blood vessels and capillaries, which normally enlarge to cool the blood, collapse from loss of fluids and necessary minerals. Symptoms of heat exhaustion include:
- increased perspiration
- intense thirst
- dizziness, fatigue
- loss of coordination
- impaired judgment
- loss of appetite
- tingling in the hands and feet
- weak and rapid pulse (120-200 beats per minute)
- cool, moist skin, and
- below-normal blood pressure
Treatment of heat exhaustion includes moving the affected person to a cooler place - shade or an air-conditioned building - and having them lie down with the feet slightly elevated. Loosen the clothing, apply cool, wet cloths, and fan them. Have them drink sports drinks or water. Do all you can to cool them down and have them checked by medical personnel. They should avoid strenuous activity for at least a day and consume plenty of liquids.
Heat Stroke is a life-threatening condition with a high death-rate. It occurs when the body has completely depleted its supply of water and salt, causing the core temperature to rise to deadly levels. The victim may progress to this dangerous condition through the stages of heat cramps and heat exhaustion, but not always. Sometimes the onset appears suddenly, especially if the heat is extreme. Often heat stroke is mistaken for heart attack, especially in the workplace. It's important to know the symptoms of heat stroke and check for them anytime a person collapses in a hot environment. Those symptoms include:
- a high body temperature (103 degrees F or higher)
- the absence of perspiration
- hot, red, and dry skin
- a rapid pulse
- difficulty breathing
- constricted pupils
Also present are the signs of extreme heat exhaustion:
- slurred speech
- bizarre behavior
- loss of consciousness
- high blood pressure
- and ultimately a spike in temperature to 108 degrees F, seizure or convulsions, and death
Seconds count in saving the person's life. Call 911, pour water on the victim, loosen or saturate his clothing, fan him, get him to a cooler place, and apply cold packs.
Preventing heat stroke is a matter of several factors. If you know you are going to be working or playing in extremely hot temperatures, condition yourself ahead of time by starting slowly and building up to more strenuous levels of activity. Allow a few days for your body to adjust. (If you're starting a new job in outdoor summer conditions, hopefully your boss will understand this principle!) Drink a little more than you think you need; do not wait until you feel thirsty. Use water and electrolyte preparations, consuming about one cup of liquid every 15-20 minutes in very hot conditions.
Avoid alcohol or caffeinated beverages such as coffee, tea, or soda pop - they do not hydrate your body well. In fact, caffeine increases your heart rate and cardiac output, sending more blood to the kidneys and increasing urination, which contributes to dehydration. Therefore, do not depend on the water in caffeinated beverages to be sufficient to hydrate your body. If you use them, drink additional water to replace what they cause you to lose. It's probably better to use soda pop as an occasional treat rather than a daily staple. Alcohol is a diuretic as well and the symptoms of a hangover are those of dehydration. (Note: Do not consume excessive amounts of water - or any liquid - all at once in an effort to re-hydrate your body. Drink slowly.)
If you begin to feel faint or develop a headache, take a break and cool off before getting back to your activity. Wear light-weight, light-colored clothing, take advantage of fans and air-conditioners, and get plenty of sleep at night. Try to perform your most strenuous and difficult tasks during the coolest part of the day.
People who are the most vulnerable to heat-stress conditions include those who fall in the following categories, though no one is immune:
- over 65 and overweight
- high blood pressure or heart disease
- taking diuretics or medications that may be affected by extreme heat
Pregnant women, especially during the first trimester, should not have a core temperature higher than 102.2 degrees F for extended periods, as that can cause a risk of abnormal fetal development. A perpetual core temperature above 100.4 degrees F in both males and females is associated with temporary infertility.
In addition to the main three heat-induced conditions mentioned above, there are additional conditions you should be aware of.
Heat Syncope is fainting or extreme lightheadedness that usually occurs with prolonged standing or suddenly rising from a sitting or lying position in hot conditions. Blood pools in the extremities rather than returning to the heart to be pumped to the brain. Contributing factors include dehydration and lack of acclimation to the conditions. Treatment is to sit or lie down, then slowly drink water, clear juice, or a sports beverage. After recovery, moving around will help to prevent a recurrence.
Heat Rash, also known as prickly heat, is a skin irritation characterized by clusters of red pimples or small blisters occurring on the neck, upper chest, in the groin area, under the breasts, and in elbow or knee creases. Gently cleanse the affected area, pat dry, and allow to "air out." Use dusting powder to increase comfort. If possible, try to work in a cooler, drier area.
Knowing a few basics about the prevention and treatment of heat-stress conditions and following them can prevent much misery and even save lives. Stay cool!