Neuroscientists may have figured out exactly how working out reduces stress


All the time, we're told that working out reduces stress.

Do some yoga, go for a run, take a swim - all common recommendations for someone with high anxiety or an overactive mind. And people who do these things tell us repeatedly that they feel better and more relaxed because of them.


But how? Can yoga really help you relax, or is it just that people who have an easier time relaxing are drawn to yoga?

Neuroscientist Peter Strick wanted to find out if there was an actual physiological connection between the brain and body that could explain why certain fitness activities might reduce stress. So, as James Hamblin explains in The Atlantic, he conducted a study in monkeys to map the connections between the parts of our bodies that control our stress responses and our brains.

To their surprise, they found a very clear connection between parts of the brain that control physical activity and parts of the endocrine (hormone) system that control stress - so clear that Hamblin says Strick is taking up a core-strengthening pilates workout.


So what's up with our core and our brain?

Right above our kidneys sit our adrenal glands, which produce a variety of hormones, including epinephrine - also known as adrenaline.

brain scan, human connectome project, fibers

Van Wedeen / Lawrence Wald / MGH / Science AAAS

We could really draw connections between our brain and our entire body.

When adrenaline spikes, we show a classic response, one that goes back to the times we had to immediately deal with threats that might kill us: fight, flee, or freeze. In modern life, those responses are far less helpful, but that stress response persists and in many cases, seems overactive, producing inordinate stress.


The previous thinking was that higher level brain processes, like those that we think of as dealing with more abstract "thought" and decision making controlled the release of adrenaline. But what Strick and his two co-authors found was a much more complex network of connections, one that was largely directly linked up to parts of the brain that control physical motion and deal with sensory input, like the feelings we get when we touch something.

Specifically, they found that the motor cortex, which controls movement, very directly controls the stress-controlling adrenal glands. The part of our brain that controls our core was especially directly linked here.

"This link could provide a neural substrate for the control of stress through 'core' exercises, such as yoga and pilates," the authors write in the study. The idea is that having a greater degree of control over our core might help us better control our stress responses too.


While the core is especially connected to the parts of our body that control stress, it's not just about our abs. The full motor cortex is tied in, meaning that all movement - arms and legs included - has some influence on the adrenaline release.

There still were connections to those parts of the cortex that deal with higher level thought, which illustrates something that makes intuitive sense: Stress is complicated. Some of the ways we regulate it may have more to do with what we think of as our "brain," our thoughts; other ways we regulate it may have more to do with what we think of as our body, our physical motion or even our sense of touch. Really, these systems all work together. And the connection between exercise and stress relief is likely highly complex; the system that Strick discovered may be just one part.

But as Strick told The Atlantic: "How we move, think, and feel have an impact on the stress response through real neural connections."


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