Exercise helps the brain respond better to stress

Being physically active can help the brain become more resilient to stress, according to a new study from Princeton University.

Researchers found that when mice were allowed to exercise regularly, their response to an anxiety-provoking event, exposure to cold water, was minimized by the activity of neurons that shut down excitability in the hippocampus.

Exercise and anxiety

Historically, studies about exercise and anxiety have shown varied results. Some have found that because exercise promotes the growth of new neurons that are more excitable than older ones, exercise should actually increase anxiety. But this new study suggests that exercise strengthens the mechanisms in the brain that prevent these neurons from firing.

For the study, one group of mice was given unlimited access to a running wheel, while another had no access to one. After six weeks, the mice were exposed to cold water for a short time. Brains of the runner mice showed a controlled reaction to the stressor, which was not observed in the non-runner mice. The runner mice showed a boost in the activity of inhibitory neurons that keep the excitable neurons "in check."

Implications

Since the brain reactions occurred almost immediately in response to the stressor, researchers say this could provide clues about how to treat stress or anxiety in humans.

Senior author Elizabeth Gould, Princeton's Dorman T. Warren Professor of Psychology, elaborates:

Understanding how the brain regulates anxious behavior gives us potential clues about helping people with anxiety disorders. It also tells us something about how the brain modifies itself to respond optimally to its own environment.

Goud notes that a disposition toward anxiety could pose an evolutionary advantage for people who are not as physically fit as others. Anxious feelings trigger an appropriate fight-or-flight response for these people in order to give them adequate time to prepare for action.

The study was published in the Journal of Neuroscience.

Source: Princeton University