How Exercise Reduces Anxiety (in Mice)

Regular readers will recall previous posts on how the benefits of exercise on weight management may have little to do with burning calories but rather with its beneficial effects on mood and stress-related eating behaviour.

A study by Schoenfeld and colleagues from Princeton University, published in the Journal of Neuroscience, now provides new insight into how exercise prevents stress-induced activation of key neurons involved in anxiety response.

Specifically the researchers studied the effect of cold water exposure (apparently a major stressor for mice) in “sedentary” and “runner” mice on the hippocampus and found that the early stress response was reduced in the latter.

They also that this benefit of running is likely due to increased local inhibitory mechanisms in the hippocampus, including increases in stress-induced release of the inhibitory neurotransmitter GABA.

Thus, these findings show that running improves anxiety regulation by engaging local inhibitory mechanisms in the ventral hippocampus.

Whether less anxiety also leads to decreased caloric intake was not studied but for people who eat to “calm their nerves”, these studies do point to a mechanism by which exercise may do the same.

@DrSharma
Edmonton, AB

Schoenfeld TJ, Rada P, Pieruzzini PR, Hsueh B, & Gould E (2013). Physical exercise prevents stress-induced activation of granule neurons and enhances local inhibitory mechanisms in the dentate gyrus. The Journal of neuroscience : the official journal of the Society for Neuroscience, 33 (18), 7770-7 PMID: 23637169

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