Exertional Heat Illness

Exertional Heat Illness Image

What is Exertional Heat lllness? (EHI)

When exercising in the heat, our body temperature rises. We sweat in order to release heat and cool the body. As sweating increases, it makes us more dehydrated, which in turn makes the body temp go even higher. Eventually more heat is staying in than can get out, and this becomes EHI.

What are the Types of EHI?

Heat Syncope is sudden dizziness, feeling faint and sometimes fainting experienced during or after exercising in the heat.

Heat Exhaustion is a heat-related illness that can occur after you've been exposed to high temperatures, and it often is accompanied by dehydration.

Heat Stroke is the most serious form of heat illness and is considered a medical emergency!

What happens to your body
when you exercise in the heat?

> Normal body core temperature is 98.6 degrees Fahrenheit.

> As you exercise in the heat, body core temperature rises.

> As the core temp rises to 102 -104 degrees, you may experience heat exhaustion, dizziness, diarrhea, or fatigue.

> As it continues to rise to 104- 105 degrees, the body's ability to cool itself, may begin to fail. “This is what happens in heat stroke”.

> Since it is difficult to know your body core temperature without a rectal thermometer, it is important to learn the signs and symptoms of EHI and know how to help prevent overheating.

What increases the risk for EHI?

> High environmental temperatures

> High humidity


> Moderate environmental conditions but intense exercise or heavy padding

> Dehydration

> Unacclimatized athlete

> Intense exercise beyond abilities and/or poor physical fitness

> High body fat

> Current or recent illness

What are signs you
might see?

+ Disoriented or confused
+ Irritable or aggressive/angry
+ Stumbling or staggering
+ Not acting like themselves
+ Slurred speech
+ Vomiting
+ Very hot dry skin
+ Fainting
+ Unconscious or lethargic

What are symptoms
you might feel?

+ Confused
+ Anger aggressive, strange feeling
+ Uncoordiated
+ Sleepy
+ Overheated and/or hot skin
+ Dizziness/ Lightheadness
+ Vomiting and Diarrhea

What might prevent
Exertional Heat lllness?

+ Acclimatize – ramp up your work out over time
+ Stay cool – try and exercise in the early morning or evening when the sun is not as intense
+ Hydrate before during and after working out

Ways to measure

+ Urine color

+ Weigh yourself before and after

Sweat rates are unique and vary based on a number of factors. Assess your sweat rate using the Fluid Loss Calculator.