DR. MIRKIN ON HEAT STROKE
The most likely cause of death during hot weather sports is heat stroke, when the body temperature rises so high that it cooks the brain (Medicine and Science in Sports and Exercise, July 2008).
Nobody should ever die of heat stroke because your body sends you warning signals as your temperature rises. Those most likely to suffer heat stroke are those who have arteriosclerosis, are overweight or are in poor shape. The treatment for a person who collapses from heat stroke is immediate immersion in cold water.
In 1965, I almost died from heat stroke in an unimportant local race in Arlington, Virginia. I am still embarrassed by the stupidity that I showed when I ignored all of the warning signs as my temperature continued to climb.
SIGNS OF IMPENDING HEAT STROKE
First your muscles are affected, then your circulation and then your brain. As your temperature starts to rise, your muscles feel like a hot poker is pressing against them.
It is normal for intense exercise to make your muscles burn, but hard exercise does not cause painful burning that feels like fire. Furthermore, the burning of hard exercise is relieved by slowing down. The muscle burning of impending heat stroke does not go away when you slow down.
As your temperature rises further, the air that you breathe feels like it’s coming from a furnace and no matter how rapidly and deeply you try to breathe, you can’t take in enough air. When you exercise intensely, you can become very short of breath, but the air you breathe will not burn your lungs. Burning in your lungs, not relieved by slowing down, signals impending heat stroke.
When you feel that the air is so hot that it burns your lungs, stop exercising. This sign means that your heart cannot pump enough blood from your exercising muscles to your skin, so heat is accumulating rapidly and your temperature is rising rapidly. Your temperature is now over 104 and continuing to exercise will raise your body temperature even further and it will start to cook your brain.
Your head will start to hurt, you’ll hear a ringing in your ears, you may feel dizzy, you may have difficulty seeing and then you will end up unconscious. Your temperature is now over 106 and your brain is being cooked just as the colorless portion of an egg turns white when it hits the griddle.
WHEN DOES HEAT STROKE OCCUR?
Almost all cases of heat stroke occur when you suddenly increase the intensity of your exercise, such as the finishing sprint of a long distance running or cycling race, or an intense run down the field in soccer.
HOW BODY TEMPERATURE CAN RISE UNCONTROLLABLY
An excessive rise in body temperature is caused either by producing too much heat or by inability to dissipate the extra heat. When you exercise, almost 80 percent of the energy that is used to drive your muscles is lost as heat. That means that the harder you exercise, the more heat you produce.
During exercise, more than 70 percent of the energy used to drive your muscles is lost as heat, so you heart has to pump extra blood from your hot muscles to your skin where you sweat. Sweat evaporates and cools your skin to dissipate the heat. The harder you exercise, the more heat your muscles produce. Everyone who exercises, particularly in hot weather, has to sweat to keep the body temperature from rising too high.
DRUGS CAN CAUSE HEAT STROKE
Heat stroke is more likely to be caused by inability to get rid of heat than by producing too much heat. Stimulants such as amphetamines or cocaine can kill athletes by preventing them from getting rid of heat by blocking sweating and blood flow to the skin. A single nasal dose of cocaine can block blood flow to the skin and sweating, to prevent a person from cooling his own body (Annals of Internal Medicine, June 4, 2002).
TREATMENT
When a person passes out from heatstroke, get medical help immediately. Any delay in cooling can kill him. Carry the victim rapidly into the shade and place him on his back with his head down and feet up so blood can circulate to his brain. Cool him by pouring on him any liquids you can find or spray him with a hose. It doesn’t make any difference what you pour on him: milk, Coca Cola, beer, or anything else.
Evaporation of any liquid cools. As you cool him, he will then wake up and talk to you and act like nothing has happened. While he’s sitting or lying there, his temperature can rise again and he can go into convulsions or pass out again, so he must be watched for at least an hour.
An athlete or exerciser who passes out from overheating should be immersed in cold water immediately to prevent brain and multiple organ damage. However, a heart attack can also cause a person to pass out and this should not be treated with cold water immersion. Therefore always get medical help immediately when you see a person pass out during exercise.
PREVENTION
Heat stroke is caused by continuing to exercise intensely in spite of all the warning signals that the body presents. Dehydration also increases your risk for heat stroke.
When you compete in sports, you need to drink before you feel thirsty, because you slow down and lose power long before you have any signals to tell you that you are dehydrated. In warm weather, trail runners raced 12 km (7.2 miles) much faster when they took fluids (Journal of Athletic Training, March-April 2010).
With fluids, they averaged 53.1 minutes compared to 55.7 minutes without fluids. Immediately after the race, the dehydrated runners had signs of greater body stress such as heart rates six beats per minute faster and intestinal temperatures .22 degrees C higher.
THIRST IS A LATE SIGN OF DEHYDRATION
You won’t feel thirsty during exercise until you have lost between two and four pints, or two to four pounds. Thirst is a very late sign of dehydration. You sweat during exercise, and since sweat contains much less salt than your blood, you lose far more water than salt during exercise.
As blood salt levels rise higher and higher, they trip off special osmoreceptors in your brain to tell you that you are thirsty. Since it takes a long time for blood salt levels to rise high enough to tell you that you are thirsty, you will be severely dehydrated long before you feel thirst.
Dr. Pinna says:
When I worked in an Emergency Department in a large city in Florida, patients with heat stroke were common. They were generally not athletes, but, rather, homeless people living in boxes, or children that fell into hot tubs. Also, elderly people who took too many medications and then fell asleep in an extremely hot area.
We had a straight forward protocol for Heat Stroke: I.V. and Monitor, instantly!
Our greatest fear was a cardiac arrhythmia (irregular heart beat) which can kill in seconds. We monitored the heart and the core temperature.
The I.V. contained saline (salt) solution, because we knew their sodium level was low. Blood for lab testing was drawn stat.
We had “Ice Blankets” always ready. These were placed under and over the patients. Additional ice packs were placed in the arm pits and the groin, where there is a heavy blood flow.
We did not drop the core temperature too rapidly for fear of a cardiac arrhythmia; and, or seizures (convulsions.)
If the patient was stable, there was no need to complicate the situation by a rapid change in the the physiology. After the patient was returned to a semi- normal state we would try to assess the mental condition, but this was difficult in the E.R. It was done in the Intensive Care Unit.
A large number of cases developed a mental disability.
My opinion: Exercise is fine, but it should not threaten your life. As they say in Italian: “Pian-piano!” Go slowly!
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