How exercise helps relieve stress

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It’s pretty commonly accepted folk wisdom that a good workout helps blow off steam and reduce anxiety. Now there are some interesting new studies suggesting that exercise may play a much deeper role in making our brains “stress-proof.” In an experiment with rats, Princeton University researchers found that the new neurons that grow in response to exercise are less likely to react to stress than regular neurons:

The “cells born from running,” the researchers concluded, appeared to have been “specifically buffered from exposure to a stressful experience.” The rats had created, through running, a brain that seemed biochemically, molecularly, calm.

Gretchen Reynolds does a nice job describing this research in the New York Times. In another experiment, rats that exercised for three weeks didn’t show signs of a calmer brain, but those who exercised for six weeks did. It’s not clear how long humans need to exercise to see these changes, but the lesson is pretty clear:

Keep running or cycling or swimming. (Animal experiments have focused exclusively on aerobic, endurance-type activities.) You may not feel a magical reduction of stress after your first jog, if you haven’t been exercising. But the molecular biochemical changes will begin, Dr. Greenwood says. And eventually, he says, they become “profound.”