I’m interested in learning more about heat exhaustion/heat stroke and in particular, how to deal with it/avoid it on long runs? What are the signs? How can you tell the difference between severe fatigue from running and dangerous heat exhaustion?
“Heat illness” is a general term that actually comprises three conditions varying in severity, symptoms, and treatment options: heat cramps, heat exhaustion, and heat stroke (which can be fatal).
While the incidence of heat illness increases as the temperature climbs, it can occur throughout the year, even in cold conditions. Regardless of one’s ability level and/or sport in which they participate, no athlete is immune. Oftentimes, there is a fine line between the categories of heat illness, and an athlete’s condition can change for the worse quite rapidly.
Heat illness can be prevented by heeding the following strategies:
Hydration – Stay well-hydrated before, during, and after exercise. Regardless of the outside temperature or your thirst level, be sure to drink water every 30 minutes of running. Sports drinks should also be consumed for runs lasting an hour or longer. Urine color is the best way to gauge your level of hydration: Pale yellow is normal while dark amber indicates a dehydrated state.
Acclimization – It generally takes a minimum of ten days to two weeks for the body to acclimate to hot and humid weather. Take it easy during this time by slowly building your tolerance to these conditions.
Prudence – Play it safe by reducing the intensity of exercise as the temperature increases. Don’t take chances – Listen to even the most subtle signals your body is communicating. This is not the time to set your sites on personal records!
Clothing – Wear light colored apparel made of synthetic blend materials (Cool-Max, Nike Dry-Fit, etc.) that wick away moisture and perspiration. Don’t overdress, however; despite the actual outside temperature, it will feel 10 degrees warmer after you run for about 10 minutes
Environmental – Take advantage of cooler conditions by planning your exercise for either early in the morning or after sunset. Use sunscreen when you must be outside during the middle of the day. And for a safe and more comfortable alternative, consider running on the treadmill or an inside track.
Awareness – Be familiar with the warning signs and treatment options for the three stages of heat illness:
- Heat cramps can occur either during or after strenuous exercise, characterized by severe pain and cramping in the legs and abdomen, faintness or dizziness, weakness, and profuse sweating. Stop running, go to cool/shady place, and drink clear juices or sports drinks. Seek medical attention if cramping doesn’t subside within an hour.
- Heat exhaustion symptoms include nausea, unsteadiness/dizziness, weakness, headache, heavy sweating, pale and moist skin, goose pimples on chest and upper arms, weak pulse, and confusion/disorientation, muscle spasms, cramps, and fatigue. Stop running, go to a cool/shady place, remove excess clothing, sponge skin with lukewarm water, and sip fluids.
- Heat stroke , unlike heat exhaustion, strikes suddenly and with little warning. It can be a life-threatening situation because when one’s cooling system fails, the body’s temperature rises quickly. Its warning signs include very high body temperature, hot dry skin, lack of sweating, fast pulse, shortness of breath or trouble breathing, vomiting, confusion, and possible loss of consciousness. Emergency medical attention is required. Do not provide fluids to drink; rather, apply ice/cold towels to the head, neck and groin areas while awaiting transport to an emergency room.
A word about hyponatremia – While staying well hydrated during endurance exercise is very important, too much of a good thing can be harmful and even potentially fatal. Hyponatremia, also referred to as “water intoxication”, occurs when fluid intake (also including sports drinks) exceeds fluid loss during exercise, resulting in an imbalance between the body's water and sodium levels. This condition can lead to nausea, fatigue and vomiting and in the most severe instances, seizures, coma and even death.