According to a new study involving mice exercise may help to safeguard the mind against depression.
Scientists have known that exercise seems to cushion against depression.
But precisely how exercise, a physical activity, can lessen someone’s risk for depression, a mood state, has been a mysterious.
The study was published last week in Cell, researchers at the Karolinska Institute in Stockholm.
>Mouse emotions are, of course, opaque to us. We can’t ask mice if they are feeling cheerful or full of woe. Instead, researchers have delineated certain behaviors that indicate depression in mice. If animals lose weight, stop seeking out a sugar solution when it’s available — because, presumably, they no longer experience normal pleasures — or give up trying to escape from a cold-water maze and just freeze in place, they are categorized as depressed.
Aerobic exercise, in both mice and people, increases the production within muscles of an enzyme called PGC-1alpha. In particular, exercise raises levels of a specific subtype of the enzyme known unimaginatively as PGC-1alpha1.
Mice were engineered to be awash in high levels of PGC-1alpha1.
These mice were then exposed to five weeks of mild stress. The mice responded with slight symptoms of worry. They lost weight. But they did not develop full-blown rodent depression.[SOURCE](http://well.blogs.nytimes.com/2014/10/01/how-exercise-may-protect-against-depression/?src=me)