Two Surprising Ways Exercise Helps You Manage Stress.

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There are many health benefits to exercise, but today, I want to focus on its positive impact on stress management. Exercise improves your ability to manage stress by widening your “window of tolerance” (aka your stress threshold).  Through regular physical activity, you can become less sensitive to stress, and it will take a larger stressor to push you over the edge. 

But HOW does exercise do this? The simple answer is that it decreases the release of the stress hormone, cortisol, in your body. But there are two additional, very surprising (and fascinating) reasons that help explain the mechanism of how exercise helps you better manage your stress responses.

The first has to do with energy. I am not talking about the stuff that propels your car. I am talking about the energy that fuels your body.  Every day, we are blessed with the same amount of energy to power our bodies and help us live our lives. It doesn’t matter if you are running a Marathon or sitting on the couch, the energy you are allotted every day is the same.  And – here is the clincher – your neighbor has the same amount of energy to work with as you do (with some very minor variations based on age and size).  As Dr. Herman Pontzer, the author of BURN, puts it, “The body maintains daily energy expenditure within the same narrow window, regardless of lifestyle.”

Pontzer has studied the Hadza people of Tanzania, one of the last remaining hunter-gatherer tribes on earth. He found that the food foraging needs of the Hadza people means that they exercise more in one day than a typical American would move in one week.  Despite this fact, they burn the same amount of daily calories as you or I.  How can this be? How can a sedentary person burn approximately the same number of calories as an active person?

On the surface, this doesn’t make a whole lot of sense until you start looking at what processes require energy within the body. We tend to think of our only energy expenditures as things like exercise, running errands, sex, and working, but it turns out that there is a lot of fuel burning that is happening behind the scenes as well. Brain function, digesting, your beating heart, your filtering kidneys, and all the other essential organ functions we rely on to stay alive require daily energy.

 

So, what if you don’t exercise? What happens to the energy that otherwise would have been used to Zumba or Pilates with your girlfriends? It turns out that your body must use all of your daily energy allotment. You can’t just choose to spend only a portion of your energy, hoping to save the rest for a rainy day.  Much like a turned hourglass, there is no halting the shifting of energy through the body. You must use it all within a 24-hour circadian cycle. If you don’t get much movement or exercise on a consistent basis, the energy budget still needs to get used up and the body will turn to using energy for creating inflammation, stress reactivity, emotional turmoil and/or unruly cell division (aka cancer). Take a moment to let that sink in…  After regular organ function, if you don’t use your energy allowance for exercise and other movement, the leftover energy must be used somewhere in the body and often the only choice is towards unhealthy and unwanted processes. Often, that energy will go towards an excessive or unnecessary stress response and the concomitant release of cortisol.  As Pontzer writes;

Constrained daily energy expenditure changes the way we think about the role of exercise in our daily energy budget.  With a fixed energy budget, everything is a trade-off.  Instead of adding to the calories you burn each day, exercise will tend to reduce the energy spent on other activities.

This explains how exercise mitigates stress (as well as anxiety, depression, cardiovascular disease, and certain cancers). Exercise is healthy because it monopolizes the daily quota of energy so that you don’t have enough juice required for stressing, being depressed, uncontrollable cell reproduction etc. This perhaps explains what Dr. Pontzer means when he says, “We have evolved to require daily exercise”.

 

The second way in which exercise works its magic on stress is a little counterintuitive. Exercise IS a stressor. That’s right. The thing that helps reduce stress is seen by the body as stress. You are physically stressing your body when you exercise. As Stanford professor, Andrew Huberman, has stated during The Huberman Lab Podcast;

The body and the brain don’t distinguish between physical stress and mental stress. It’s all nervous system. Remember that. It’s just cortisol and adrenaline.  There’s no special hormone just for physical stress versus psychological stress.

So, what is happening then? How is exercise a stress-reducer when it is chemically identical to a psychological stress response? The key difference is that exercise is a short, predictable, and controllable stressor. As such, exercise is a way of training or preparing the body for other less predictable, uncontrollable, and longer duration stressors. Exercise inoculates against stress by introducing short bouts of cortisol and adrenaline release which, in turn, teaches the body that it can successfully recover from stress.

 

Exercise helps you manage stress by monopolizing energy so that you don’t have enough reserve to stress-out and by training you for future stress. 

 

Ironically, if you are depressed, stressed, or in chronic pain you probably don’t have a lot of energy to exercise. Moreover, as I am noticing with a lot of my patients, exercise can feel too much like the uncontrollable stress they are trying to escape. Exercise can feel like a panic attack. The way out of this vicious cycle is to change our definition of exercise.  Even the smallest amount of movement is exercise. The idea is to trick the body into enjoying movement in short bouts until more intense activity becomes tolerable. Eventually, the goal is to shift the use of energy from something that is adding to your discomfort (inflammation, emotional dysregulation, excessive adrenaline release) to something that might initially feel uncomfortable (and near impossible), but in the long run protects and benefits you. You can call it a change in habit, but perhaps it would be best to think of it as a shift in the way you are allowing your body to use energy. 

 

I want to be very clear… I am not shaming anyone into exercising. I am offering an alternative way of thinking about why you might add exercise to your daily routine.  This may be very difficult to do depending on your life circumstances. If your job is sedentary AND stressful and you are the only bread winner in the family, adding exercise to your schedule can feel punishing and totally unfeasible. In such cases the need to exercise can be a stressor. It is important to remember that movement IS exercise, and it doesn’t have to be big, or intense, or fancy.  You just need to move your body to create short, predictable physical stress and use up some of that daily energy.