If you had to come up with a definition of "stress," you might start talking about electric bills, social drama, or an overly demanding boss. Maybe you’re even one of those people who thinks of a workout as stress relief: go work up a good sweat, forget all the frustration of the day…
But if you asked an athlete to define “stress,” they might start talking about training volume or total running mileage. In other words, they see exercise as a stress that they have to manage and recover from.
So who's right? Both of you!
Stress is anything that disturbs your ability to stay in a healthy state of balance. Physical stress and psychological stress are two aspects of the same thing. (And if you want to see some studies proving that, just keep reading – they’re coming). But the great thing about humans is that we can actually bounce back stronger from some kinds of stress, exercise being the very best example. It’s called hormesis, and it’s basically the “what doesn’t kill you makes you stronger” principle of biology.
This review goes over a bunch of studies on exercise and stress. In the short term, exercise can make people feel all different things. But in the long term, regular exercise (physical stress in manageable doses) increases resilience to psychological stress.
So here are 4 ways that exercise can boost your psychological stress resistance, and 1 way it can totally backfire.
1. It’s a Leg Up for your Immune System
A while back, we reported on exercise and your immune system. If you overdo it and take your workouts to extreme levels, the stress can wear you down and wreck your immune health. But in moderate doses, plenty of evidence suggests that regular exercise is great for immune function.
Now guess what’s hard on your immune system? Psychological stress! Chronic psychological stress impairs immune function and makes you more vulnerable to disease.
Consistent, regular exercise will build up your immune system. When the psychological stress comes (and it’s going to come – nobody can avoid stress forever), your body will be ready.
2. It Blunts the Hormonal Stress Response.
Just like physical stress, psychological stress starts off a whole cascade of hormones. Cortisol is probably the best-known, but there are plenty more, like norepinephrine (if you’ve ever been startled and suddenly had a huge surge in physical energy, you’ve felt norepinephrine in action).
Regular exercise reduces baseline levels of stress hormones and blunts the hormonal response to sudden psychological stress. That’s great! It means that a mental or emotional stressor (hard day at work, screaming kids in the grocery line, traffic jam when you’re in a rush) will feel less intensely “stressful” and do less damage to your body and brain.
3. It Changes your Gene Expression.
Everyone is born with a certain set of genes and there’s nothing any of us can do about that. But you can change the expression of your genes – basically which genes get “turned on” or “turned off.” This is called epigenetics. (For the interested, epigenetics is one of the big factors in rising obesity rates, which you can learn about here.)
In general, exercise has a bunch of epigenetic benefits, and among them are changes in gene expression that increase mental stress resilience. That means that if you’re genetically prone to stress, a consistent exercise program can actually help reduce that problem.
4. It’s Anti-Inflammatory
OK, technically it’s a little more complicated than that.
A single workout is pro-inflammatory, because a single workout is a stressor and that’s what stressors do: they cause inflammation. Both exercise and public speaking increase proinfammatory markers. Whether you go for a hard run or do something nerve-wracking, your body has to deal with the same inflammation stress.
But in the long run, regular workouts with enough breaks to recover have been shown again and again to reduce inflammation. It’s the hormesis response again: you recover from the stress and bounce back stronger.
Quite a bit of recent research suggests that reducing inflammation might help reduce stress and anxiety (here’s a review with a free full-text; the inflammation part is in section 4). So by reducing inflammation, regular exercise helps manage the stress response.
+ 1. It can Backfire if…It’s an Overload
The thing about the “bounce back stronger” response is that it only works if you actually give yourself enough recovery time to bounce back. The more stress (mental + physical) you put yourself through, the more recovery you need. And most of us only have so much ability to recover. After a certain point, any more stress (mental or physical) is just overload.
Here’s a fun fact: mental stress and anxiety predict sports injuries pretty well. Translation: mental stress + physical stress can combine to make one big stress-ball of overload. Athletes who are mentally stressed out are adding more stress on top of the stress they’re already dealing with from their sport. They’re exceeding their ability to recover, so of course they get injured! Training overload without enough recovery time is a very fast way to hurt yourself, and a high level of psychological stress could easily tip “training load” into “overload.”
Overload doesn’t make anyone stronger (mentally or physically). It just wears you down.
Remember that all the benefits of exercise came from regular, consistent exercise. In the short run, a workout actually increases stress. The benefit of exercise comes from the long-term buildup of resilience as you recover from workouts. You obviously can’t possibly get that benefit if you’re overwhelming yourself and not taking enough recovery time.
Play the long game. Know your own ability to recover, and adjust your exercise intensity to the level of mental stress in your life. Keep the total sum of mental + physical stress within your own ability to recover. It’s fine to take a light week or month when you need it.