How powerful is exercise against depression?

Exercise may help protect against depression thanks to a previously unknown effect on engaged muscles, according to the results of a new study in mice. This discovery can be very significant for anyone whose level of stress threatens to threaten emotional stability.

Mental health experts have long known that even mild, repetitive stress can contribute to depression and other mood disorders in animals and humans.Scientists also know that exercise protects against depression. Studies show that exercise somehow helps people and animals to be resistant to emotional instability. However, until now it has been a secret how exercise as a physical activity can reduce the risk of depression as a form of mood. That's why for the purposes of this new study, published last week in the journal Cell, researchers from the Karolinska Institute in Stockholm studied the brain and behavior of mice in a very original and new way. The emotions of mice are, of course, unknown to us. We cannot ask them if they are happy or sad. Instead, the researchers defined certain types of behavior that indicate depression in mice. If the animals lose weight, stop seeking sugar when it's available – presumably because they're no longer experiencing the usual pleasure – or give up escaping the cold water maze and simply freeze in one place, they're labeled as depressed. In this new experiment, after five weeks of frequent, intermittent, low-intensity stress, such as tethering or a mild electric shock, the mice began to behave exactly like that. They became depressed. The scientists were then able to test whether exercise reduced the risk of developing depression by first having the mice run. However, they knew from previous research that they would get confirmatory results. They wanted to see it happen.