Twenty years ago, Korey Stringer died of heat stroke at age 27. He was 6′ 4″ tall, weighed 335 pounds and was an All American tackle at Ohio State University. He became an All Pro lineman for the Minnesota Vikings in 1995.

At pre-season practice on Tuesday morning, July 31, 2001, the temperature index reached 110 degrees. The Vikings wore full pads and helmets for morning practice, which was a bad decision because extra clothing and padding prevent the body from getting rid of heat.

Stringer found it very difficult to keep up with the other players, even though he was a great athlete and was, in his own words, “in the best shape of my life.” Stringer vomited three times during practice and complained of weakness and dizziness, collapsed during a drill, and breathed heavily when he walked to an air-conditioned tent. The trainer in the tent observed Stringer’s condition and offered him water. Stringer remained in the tent on an examining table for forty-five minutes, until the trainer called for a cart to take Stringer back to practice. When Stringer rose to meet the cart, he suddenly laid down on the ground and became unresponsive. At this point, the trainer summoned additional help and applied ice towels to Stringer’s body (Sports Law Journal, Villanova University, 2005; 12(1)). He was taken by ambulance to the hospital and when he arrived, his temperature was 108.8 degrees.  He died the next morning. A very high body temperature cooks the brain so you lose brain functions, stop breathing and your heart stops beating.

Heat Stroke Risk Factors
Heat stroke means that the body temperature rises so high that it cooks the brain so your body stops functioning and you can die. Today, twenty years after Stringer’s death, nobody has changed his diagnosis of heat stroke. I have no new information on his death, but I do know that certain drugs and supplements increase a person’s risk for heat stroke.

During the lawsuit that followed his death, the attorneys for the Minnesota Vikings claimed that he frequently used a supplement called Ripped Fuel, which contains ephedra. His training camp roommate said that Stringer had used Ripped Fuel the morning of the day he collapsed. No traces of ephedra were found in Stringer’s body, but the Vikings claimed that toxicology reports did not test for ephedra. Reports state that his body was tested only for a diuretic called hydrochlorothiazide (Sports Illustrated, February 25, 2003).

Some athletes take ephedra to lose weight or to be more aggressive. Ephedra is a stimulant and all stimulants, including amphetamines and cocaine, can cause a sudden uncontrolled rise in body temperature. A single nasal spray of cocaine blocks blood flow to the skin and sweating, to prevent a person from cooling his own body (Annals of Internal Medicine, 2002;136(1):785-791). Ephedra increases risk for heatstroke by increasing heat production by making your heart beat faster and stronger, and preventing heat loss by constricting blood vessels near your skin and decreasing sweating.  The International Olympic Committee, the National Football League, the National Collegiate Athletic Association, minor league baseball, and the U.S. Armed Forces have all banned the use of ephedra.

I’m Not So Smart Either
Almost all cases of heat stroke occur when you suddenly increase the intensity of your exercise, as in the finishing sprint of a long distance running or cycling race, or an intense run down the field in soccer or football. In 1965, I almost died from heat stroke in an unimportant local race near Four-Mile Run in Arlington, Virginia. I am still embarrassed by the stupidity that I, as a doctor, showed when I ignored all the warning signs as my temperature continued to climb. First your muscles are affected, then your circulation and then your brain.

Muscles: 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.

Circulation: 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. Continuing to exercise will raise your body temperature even further and it will start to cook your brain.

Brain: Your head will start to hurt, you may hear a ringing in your ears, you may feel dizzy, you may see spots in front of your eyes or have difficulty seeing and then you can end up unconscious. Your temperature is now over 106 and your brain is being cooked just like the colorless portion of an egg that turns white when it hits the griddle.

Treatment of Heat Stroke
When a person passes out from heat stroke, get medical help immediately. Any delay in cooling can be fatal. (Caution: a heart attack can also cause a person to pass out and you do not want to cool a person suffering from a heart attack). A person who is suffering from a heat stroke will have skin that feels incredibly hot. Carry the victim rapidly into the shade and place them on their back with head down and feet up so blood can circulate to the brain. Cool them by pouring on any liquids you can find or spraying with a hose.  Evaporation of any liquid cools. As they cool down, they will wake up and talk to you and act like nothing has happened. While sitting or lying there, their temperature can rise again and they can go into convulsions or pass out again, so they must be watched for at least several hours, usually more.

Take it Easy When You Exercise in Hot Weather
During exercise, almost 80 percent of the energy used to drive your muscles is lost as heat, so your 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 has to sweat to keep their body temperature from rising too high, particularly in hot weather.  Stay well hydrated, but realize that too much fluid (which can result in low blood sodium or Hyponatremia) can also be harmful.

Korey Stringer
May 8, 1974 – August 1, 2001