How to Prevent and Treat Heat Stroke

Exertional heatstroke can cause devastating damage, but it can also be treated quickly

The key thing for people’s outcome is the number of minutes their temperature is over 105 degrees,” says Douglas Casa, CEO of the University of Connecticut’s Korey Stringer Institute, named after the Minnesota Vikings offensive lineman who died of heatstroke during an August 2001 training camp. Survival is highly likely if the core temperature is brought below 104 degrees within 30 minutes. Here are Casa’s tips on prevention and treatment.

Avoid exercising in high temperatures, or choose cooler parts of the day and stay in the shade. If you do exercise in the heat, wear pale-colored, loose-fitting, lightweight clothing, and acclimate to the conditions by gradually increasing your output over 7 to 14 days. 

How much water to drink is the subject of some debate. For recreational athletes, Casa suggests hydrating based on thirst. High-level endurance athletes should account for other factors, such as sweat rate. Avoid drinking alcohol before and during strenuous outings. 

Heatstroke symptoms vary. Many victims are still conscious, and some have seizures or vomit while others do not. Suspect heatstroke if the person can no longer support their body weight, speaks irrationally, or is hyper-irritable or confused. (Casa knows of heatstroke victims who punched a police officer at the finish line of a race.) To get a true reading of core temperature, use a rectal thermometer. 

“Cool first, transport second” is the oper­able concept when it comes to heatstroke. With mere minutes to act, a victim should be cooled down before being taken to an emergency room. Immersing the body in a cold bath lowers temperature the fastest, dropping it one degree every three minutes if the water is circulating. 

Exertional heatstroke in the backcountry presents additional challenges. Anything that cools the victim is helpful, but the best options are to immerse them in a lake, river, or stream, or wrap them in fabric drenched with ice water from a cooler. It’s important to cool as much of the body’s surface area as possible. In the absence of cold water, seek shade, wet the person’s clothing with your water bottle, and fan them. (For heatstroke prevention tips aimed specifically at desert hikers, go to Ariel's Checklist.) 

posted Saturday July 9th
by Outside