Avoid heat illness while running

With summer approaching, it’s important that you understand the body’s response to training in the heat.

Training in the summer is one of the best times of year. The sun is shining, and you can finally shed all the layers from winter. But you have to be careful. Heat illness is a serious risk. It can come on fast if you don’t recognize the signs.

I’m a Certified Strength and Conditioning Specialist and Running Coach, and in this article, I cover the two types of heat you experience when running in the hot weather, how heat affects people differently, and the different levels of heat illness and how to prevent it.

What is Body Heat?

Your body experiences two types of heat when you exercise in a hot environment. The first is internal heat.

When your body gets hot, your blood vessels start to expand. This process is called vasodilatation. When your body experiences heat vasodilation, it’s a physiological response to help regulate your internal temperature by increasing blood flow to the skin’s surface. This widening of blood vessels allows for more heat to be released from the body, helping to cool you down.

The second type of heat is external. The weather can cause external heating to vary in intensity depending on direct or indirect sunlight and wind direction. So, the location of your run will determine the degree of external heat you experience. 

Does Everyone Experience Heat the Same?

Heat acclimation can change from individual to individual. Some individuals acclimate to heat quickly, while others may take much longer.

Those who tend to take longer include:

• Athletes with a higher amount of body fat. The more body fat the less efficiently the body can dissipate heat.
• Generally, the larger the athlete, including those who carry a lot of muscle mass, the more energy is required to reduce body heat. 
• Novice or less conditioned athletes may also be more affected by heat.

Here’s the Good News…

Your body will adapt over time to the environment in which you train. So, if you’re training in a hot climate, your body will actually:

• Increase in sweat rate and a corresponding decrease in sweat concentration
• Lower skin and core temperature 
• Lower heart rate during exercise—This means returning to normal levels because heat will initially increase heart rate.
• Increase fluid and cardiovascular stability
• Decrease the metabolic cost of exercise

What Does It All Mean?

This means that after the initial discomfort of training in the heat, your body will gradually become more comfortable in warmer temperatures.

For most people, heat adaptation occurs between 1-2 weeks.

One thing to note if you train in hot AND humid environments…

When it’s humid out, sweat evaporation slows down due to the moisture from humidity. Though wiping away the sweat is tempting, it’s better to leave it to evaporate naturally to provide that cooling benefit. 

Heat Acclimation

There are many different ways to acclimate to heat. Saunas, overdressing, and climate chambers are often used to help professional athletes acclimate faster. The simplest and easiest way, however, is to gradually increase your time exercising in warm weather.

Let’s talk about some of the risks of training in hot climates.

Heat Cramps

Heat cramps (not exercise-based) are often treated with cessation of activity, moving to a cool, shaded area, and drinking an electrolyte beverage. Stretching and massaging the cramped area can also help to alleviate the pain. Heat cramps are temporary and tend to go away after a few minutes.

Heat Exhaustion

Heat exhaustion occurs when the body’s natural temperature regulation system begins to break down. Due to a lack of hydration and minerals, the body’s capillaries reduce in size, reducing its effectiveness in cooling itself. Common symptoms include:

• Dizziness
• Heavy sweating
• Confusion
• Nausea
• Weak, rapid pulse
• Low blood pressure
• Excessive thirst
• Hyperventilation
• Loss of appetite
• Anxiety

Heat Stroke

This is the most serious of the three categories of heat illness and can be fatal. While an individual may have experienced heat cramps and exhaustion before heat stroke, it is not always the case. Heat stroke is caused by the body’s lack of water and electrolytes, which can cause the body to shut down. Symptoms include:

• Rapid heart rate
• No sweating
• High body temperature (>103)
• Red, dry skin
• Confusion
• Vomiting
• Nausea
• Erratic behavior
• Difficulty breathing
• Constricted pupils

Prevention of Heat Illness

Thankfully, taking a few precautionary measures can help prevent heat illness from occuring.

Prevention strategies include:

• Hydrating
• Gradually acclimating to heat
• Taking breaks
• Wearing proper clothing (e.g., light colors, wicking)
• Awareness of the body’s response to the heat

Pre-Race and In-Race Cooling

Sometimes there may be a situation where you are traveling from a cooler climate to a hotter climate. This means you won’t have time to acclimate. The most important thing is to find ways to stay cool throughout the race.

Here are a few strategies you can you:

• Pre-hydrate, go into the race well hydrated and hydrate with cool fluids throughout
• Pack ice on your torso, ice your neck and head (via ice bandanas, ice collars, and special ice hats)
• Ice your peripheral arteries (put ice down arm sleeves)
• Wear loose and light-colored clothing
• Limit conductive heat (avoid dark colors)
• Drink cool fluids after the race

Conclusion: Preventing Heat Illness on Summer Runs

With a few simple precautions and preparation you can make training in the heat an enjoyable and safe experience. Learn to recognize the signs so you don’t become another statistic.

If you’re ready to take your training to the next level check out my coaching page and schedule a consultation so we can get started asap!

Remember to subscribe to the Outdoor Muscle YouTube channel. Leave a comment if you want me to explore any other strength and conditioning topics.

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