Medicine for the Outdoors
Medicine for the Outdoors

Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.

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When It's Too Hot: Tips for Staying Cool in the Heat

There are certain topics that will be appropriate to cover in regular cycles as posts to this blog, particularly if they are about situations where timely information might prevent a bad medical problem. Heat illness, and in particular heat stroke that leads to death, is one such problem. So, given the fact that at least 27 deaths have been reported in California due to this recent heat wave, I believe it is time to revisit the topic.

In our state, and across the nation, we seem to be witnessing higher temperatures during the summers than have historically been the norm. Whether or not this can be definitively attributed to global warming is a matter of debate, but the fact is that when people get too hot, they can rapidly become ill, and even die. Humans are not that well adapted for extremes of temperature. While cold can in certain circumstances be protective, heat is a destroyer. Humidity makes the situation worse, as it impedes evaporation of sweat, which is a major body cooling mechanism for humans. The National Weather Service has a heat index that roughly correlates air temperature and relative humidity to derive an "apparent temperature." At all temperatures, humidity makes the situation worse. For instance, at an air temperature of 85 degrees Fahrenheit, if the relative humidity is 80%, the apparent temperature is 97 degrees F. So, you must be extremely careful not to overdo it when the thermometer is rising.

The most effective ways to avoid heat-related illnesses are to:

  1. Stay well hydrated. Thirst is often not be an adequate indicator of how much water you need to drink, particularly when you are tired and during exertion. Be sure to keep up with your fluid losses by drinking enough so that you have to urinate often. If your urine is dark in color, then you are likely dehydrated, so keep drinking. You want your urine to be light-colored. Unless your doctor tells you otherwise, supplement water with an electrolyte-containing beverage, such as Gatorade. If the beverages you drink are a bit cool, they may be more palatable. 
  2. Curtail heavy exercise when it is hot, and particularly when it is humid. Above 75% humidity, you will have difficulty evaporating sweat, so your natural cooling mechanism is impeded.
  3. Wear a broad-brimmed hat in the sun. Better yet, stay out of the sun.
  4. When you feel hot, immediately seek a cooler location. 
  5. Don’t bundle yourself in hot clothing in the heat. Don’t try to lose water weight as part of any weight loss program. 
  6. Avoid alcohol and other beverages (such as tea and coffee) that act as diuretics.
  7. If you are supervising children, athletes, or laborers in the heat, pay close attention to their behaviors. Anyone who seems overly tired, confused, or inappropriate may be on the verge of serious heat illness. Get them to a cool location, have them shed articles of clothing, and begin to lower their body temperature. 
  8. The second leading cause of death, after head injuries, in athletes is heat stroke. It is cruel and unnecessary, and particularly dangerous, to withhold water from athletes during practice and games. Furthermore, they are at great risk for overheating when exercising while wearing occlusive uniforms, hats, and helmets. Provide frequent water breaks and rest periods for all athletes.
  9. Observe elders closely, particularly those who reside in dwellings without air conditioning.
  10. Never leave a child or pet unattended in an automobile in the heat. The internal temperature of a car in the sunlight can rapidly rise to the point that the passengers are overwhelmed. 
  11. Be particularly vigilant if you are taking medications that affect your body’s ability to control its temperature. Have your pharmacist review all of your medications in order to let you know whether you are particularly vulnerable to the heat.
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About the Author

Dr. Paul S. Auerbach is the world’s leading authority on wilderness medicine.