On a lovely Sunday afternoon, with the household chores done, you decide you want to get out and enjoy the day. You feel like running alongside the river - your favorite route. You load the jogging stroller in the trunk, put the baby in the car seat and off you go. As you drive down the freeway, an electronic billboard tells you it is '2:33' and 85°F (30°C).

Having decided that it was perhaps a little too warm to run today, you take a leisurely walk through the park, resting often on a bench under the shade of the trees. During one rest stop, a jogger, flushed and breathing very heavily, staggers towards you and falls to the ground. You move quickly towards him, instinctively touch his head, which seems extremely hot to the touch, though he is still sweating.

If you were our stroller in the park, what would you do for the collapsed jogger? The jogger is very likely suffering from heat stroke. This is a life-threatening emergency. Call 911.

After the EMTs arrive and take the jogger off to the hospital, you head home for a cool drink and air-conditioning. Soon, the baby is napping and you are about ready to settle down on the back porch with your lemonade but are interrupted by the pained cry, on the other side of the fence, from your neighbor, an elderly, slightly overweight woman.

The fluid in an engine must circulate properly to be effective. The same is true of blood.

"Is anything the matter?" you call out, as you hurry to look over the fence. You find her sitting on the grass, rubbing the muscles in the back of her legs. "I have been working out here all afternoon pulling weeds" she says. "Now, whenever I try and move, I get cramps in my legs. My arms are beginning to feel tight too. Am I having a heart attack?" she asks, worried.

What do you think is wrong with the next door neighbor? Yes, it's heat stroke.

Cramps in the legs (or arms) after someone has been working in the heat are called heat cramps. They can be easily treated using home remedies. To find out how, read on.
In order to understand a little about heat illness, it is useful to understand how the body manages to keep cool. Drs. Yarbrough and Bradham, in Emergency Medicine: Concepts and Clinical Practice, use an automotive analogy. They liken a person to a car. The body itself is the engine. The harder we work the engine, for example when we exercise, or if we get a fever, the more heat we produce. Our skin is the radiator of the car. It is the place where most of our cooling occurs. How does this happen?

When we perspire, sweat lies on the surface of the skin. Sweat evaporates off the skin and this evaporation carries away heat and cools the skin. We also lose heat by radiation and conduction (for example, if we lean against a cool surface or are in a cold environment). These losses are usually small in comparison with the heat lost through evaporation, especially in the situation we are discussing, where the air temperature is high. Indeed, in hot environments we may actually GAIN heat by radiation. If, for example, the air temperature is higher than the body temperature, then the body will gain heat from its environment by radiation. However, people do live in climates where the air temperature is above 98.4°F and not all of them have air conditioners! For these people in hot climates, evaporation is the dominant method of keeping cool.

Like any radiator, our skin cooling mechanisms can only be fully effective if there is sufficient water in the system. Thus, people who become dehydrated are not going to be able to produce as much sweat as they may require and are going to be at risk for heat illness. Also, if you cover the radiator, evaporation is going to be less effective. Tight or restrictive clothing prevent the sweat from evaporating and cooling will be less effective.

Cramps in the legs (or arms) after someone has been working in the heat are called heat cramps. They can be easily treated using home remedies.

The fluid in an engine must circulate properly to be effective. The same is true of blood. If there are problems with blood flow, so called 'hardening of the arteries' or arteriosclerosis, then, circulation is going to be less effective and the patient will be at risk of heat illness.

If the pump (the heart) does not work properly, then again the patient is potentially at risk from heat illness.

In the car, there is a thermostat that regulates the cooling of the engine. The human thermostat is located in the brain in an area called the 'hypothalamus'. Damage to the hypothalamus, for example after a stroke or after a previous episode of heat stroke, will render the patient at significant risk for heat illness.

Now that we understand a little about how we keep cool during hot summer days, we can use some of this information to help us understand what was happening to the jogger and the neighbor, as well as what they might have done to prevent their conditions.

In the hot days of summer, almost more important than the temperature, is the humidity. When the air is very humid, it is difficult to evaporate sweat efficiently and, thus, it is more difficult to keep cool. Weather stations try and allow for this effect when they quote the 'apparent temperature' or when they talk about the 'heat index'. The combination of even moderate temperatures, for example in the mid to high 70s with high humidity, can render athletic activity hazardous. Persons who are not fully acclimatized should not exert themselves when the 'heat index' rises into the upper 80s, and great care should be taken by anyone who is exerting himself or herself when the heat index is into the 90s. When the index is so high, it's a good idea, no matter how fit you are, to avoid heavy physical exertion.

Two Kinds of Heat Stroke
The jogger exhibited some of the classic signs of acute exertional heat stroke. In general, exertional heat stroke tends to affect young, healthy people, most often males. It usually occurs in relationship to extreme physical activity in the heat. Though victims may still be sweating, they have neurological abnormalities -- confusion, disorientation or loss of consciousness. Sometimes, they may have a seizure.

Before professional help arrives, is there anything you can do for someone who you suspect may have heat stroke?

First, make sure they are not choking, are breathing and that their heart is pumping. Doctors call this the 'ABCs' - Airway, Breathing and Circulation - and we always check these things first.

If the patient is not breathing, we need to start rescue breathing. With the victim lying on their back on the ground, we place a handkerchief or cloth over the victim's mouth. We then put one hand on their forehead and another under the neck, which tends to thrust the chin out. The effect of this maneuver is to straighten the victim's airway a little and move their tongue away from the back of the throat, where it may be blocking the airway. Now we place our mouth over the mouth of the victim and blow slowly and evenly for about two seconds. We then remove our mouth for about three or four seconds and blow again.

After two 'rescue breaths,' we need to check the pulse. We do this in the neck. Feeling for the Adam's apple, we move our fingers off to the side into the little groove. There we find the carotid artery. If there is no pulse, then we need to start CPR (cardiopulmonary resuscitation). The next thing is to call for help. Try to avoid leaving the person alone in case their condition worsens. Ask someone to go and call 911.

If the person is breathing and has a pulse, the next stage is to start the cooling process as quickly as possible. Move the person into the shade if possible. Remove any tight or obstructive clothing. If you have any water, use a cloth to wet the skin and then improvise a fan to blow air over the patient. A book or a newspaper waved vigorously over the patient should work well. Try and keep the skin moist - evaporation, you recall, is the best way to cool the body. Once the EMTs arrive, they will probably put in a couple of I.V. lines, move the person into the air conditioned ambulance and continue your cooling efforts until the patient gets to hospital.

It is very important to realize that, in heat stroke, the one thing that seems to make the biggest difference as to whether the patient will survive (each year people in the United States do die from heat stroke) is how long it takes to cool the person down. The quicker they are cooled, the better their chances of making a good recovery.

There is another type of heat stroke - the so-called 'Classic' heat stroke. This type tends to be more common in older persons, especially those who are chronically ill, sedentary and often on a number of different medications. In these patients, if we remember our car analogy, it is the pump and the tubing that is faulty, together with, perhaps, the thermostat. These patients, who may be in nursing homes, hospitals or at home, will present confused and usually very dry. They, unlike the exertional heat stroke victim, will not be sweating. Management of these patients involves cooling and replacement of fluids.

The best treatment of all, though, is prevention. If you have an elderly neighbor, especially if they are confined to the house, check on them during hot weather. Make sure they have at least a fan blowing cool air on them. Many older persons cannot afford air conditioning and this may be their only method of cooling. Make sure they have access to plenty of water. Put a jug and glass within their easy reach. Some cities provide air-conditioned areas for their elderly citizens during heat waves. If necessary, think about taking your elderly neighbor or friend there.

Having managed the overheated jogger very efficiently, by cooling him with water from a spray bottle and fanning him vigorously with the Sunday funnies, what can we do for the cramping neighbor?

Heat Cramps
Heat cramps, unlike heat stroke, are not life threatening but are characterized by painful spasms of the skeletal musculature, particularly the legs. The body temperature is usually normal. The cramps usually affect muscles that have been exercising and are related, we believe, to a deficiency of salt. They can be rapidly alleviated by the use of the rehydration fluids, such as Gatorade. If these are not available, then 1/4 to 1/2 of a teaspoon of salt dissolved in a quart of water will do the trick. The gardening neighbor should drink a couple of quarts of this solution, rest in the cool and will soon feel better. If she does not respond to cooling down and drinking replacement fluids and gets worse, for example, if she starts to vomit profusely, medical attention should be sought urgently, as she may need I.V. treatment.

Heat Exhaustion
Though not as severe as heat stroke, heat exhaustion is a more serious type of heat illness. In contrast to heat stroke, the temperature control mechanisms of these patients do remain intact but the patients are fluid depleted and sweat profusely. As a result, these patients are weak, complain of headaches, nausea, vomiting, dizziness and fainting. Usually, the patients are young active people who have been exercising or working in the heat. Roofers, construction workers and landscape gardeners seem to be at particular risk. Treatment includes rest, rehydration (which often needs to be given intravenously) and cooling.

Take Home Messages
  • Be careful when exercising or exerting yourself in the heat, especially if the humidity is high
  • Prevention is very important. If you must exercise, then drink plenty of fluids and take fluids with you while exercising or working.
  • At the first sign of trouble - weakness, cramps, nausea or vomiting - STOP exercising, seek a cool place and drink fluids. If you don't feel better soon, seek urgent medical attention
  • If you come across someone who seems to be affected by the heat, call for help and try to cool them down with water sprays and fanning, while waiting for the ambulance
  • The quicker someone is cooled down, the better their chances for a good recovery
  • PREVENTION is key. Think about your elderly neighbors and friends in the hot weather. Ensure they have access to a method of cooling, and to plenty of fluids
  • Don't forget about children outside playing. They need plenty of fluids through the day.
  • And, finally, pets can get heat illness too. Make sure they have access to a shaded area and to a plentiful supply of fresh water.