We are in the thick of summer. For us parents, we are navigating the last few weeks of summer break before schools starts. Printing off the school supplies lists and finding one more family activity before the fall school schedule takes hold.

We’ve had recording-breaking heat (in Indiana at least), and the weatherman warns us how the heat domes across the United States bring forth sweltering heat, humidity, and storms at its edge.

• Exercise outside?
• In a gym with no air-conditioning?
• Or maybe in Florida when 9:00 am brings on 90-degree heat to start your day?

The Heat As A Variable

Many things get us going, increasing the probability that we will work out.

Many things pause us, challenging that same probability.

From a behavioral perspective, the heat (or “feels like” temperature) is an environmental event that changes the value of certain outcomes and the probability of certain behaviors to occur.

Depending on our learning history with these exercise variables, the heat may function as an environmental event with meaningful predictive power.

Working out during the summer, provides predictable outcomes:

• You will be hot
• The heat increases your heart rate
• The heat increases your perspiration (because your body wants to cool down!)
  

…which leads to sweaty clothing and possible discomfort.

Heat: An Aversive Stimulus

On that last point, I say possible as the heat and sweaty clothing may function as an aversive stimulus. Heat is a stimulus. Our reaction to it defines whether it is aversive or not. Through our experience with exercising in the heat, most of us will try to remove as much heat as possible. We engage in behavior to avoid such consequences or remove the stimulus entirely.

These avoidance behaviors may take the form of:

• Turning on the air-conditioning
• Checking out weather apps
• Exercising outside before the temperature gets too high
• Removing t-shirts before, during, or after a workout
• Avoiding exercise all together
  

As a counter-example, UFC fighters and wrestlers seek heat and sweaty environments: adding clothing, sitting in the sauna, and perpetual exercise for the sole purpose (or function) of losing weight ahead of a match.

In this case, the heat may still feel aversive, but behaviorally speaking, these athletes are not actively engaging to remove that stimulus.

Heat and Response Effort

In behavior analysis, we commonly use a term to indicate how difficult an activity is: response effort.

We borrowed this term from the lab, as researchers analyzed a rat’s lever press to obtain a pellet. The energy required to press a lever could be quantified. Higher response effort required more energy to push the lever. It was “harder”.

This term works well for exercise effort. Exercise is harder in the heat in the sense that your body has to complete an exercise while maintaining a consistent body temperature. All things being equal, running a 5K is easier in 70-degree heat than 90-degree heat.

Heat increases the response effort of exercise.

Heat In Your World

Think about your exercise routine.

• Are you less likely to exercise in the heat?
• Engage in certain behaviors to mitigate the heat? (See list above.)
• Does the heat not change your routine?

Most importantly, stay safe, drink lots of water, dress for the weather, wear sunscreen. Engage in all the heat-related safe behaviors to increase your chances of exercise success.

This turns the conversation from, “I don’t know why I didn’t work out,” to “It’s hot again, and I need to plan my day around the high temperature because I want to maintain my current program and stay safe!”

I focused on heat in the blog, but the cold can do it too. Think about the behaviors in reverse: Do you bundle up? Have the right cold gear? Turn on the heat?

While there are many variables at hand during one’s fitness journey, the heat is just one of many.

Stay safe, my friends.