Exercise and moving doubles the production of new brain cells.

The photo I attached to this article, was taken by a grate sports photographer from Tallinn - Johannes Paul Tamm.

Brain cells growth is a very important factor for both - physical and mental health. Up to one third of the cells in the hippocampus are exchanged for new ones during lifetime. Depressed people get too few new brain cells, which also results in impaired memory and concentration. Physical activity causes the brain to produce new cells and with daily exercise the healing can gradually begin. Sedentary people are a risk group for Alzheimer's and dementia, whereas older people, who are physically active, can for the most part, maintain good memory and mental acuity until quite old age.

One part of the brain's hippocampus - gyrus tentatus - makes sure, that we are able to see the most nuanced connections in our memories, for example, by wondering, if we know someone in company, who looks familiar or why he seems so familiar, when we actually don't know him. When we observe the height, hair color or facial features of this person, our gyrus dentatus tries to determine, whether we know the person or not. Because many things remind us of something we have experienced before, and many people remind us of someone, it is the brain's "pattern separation", that allows the gyrus dentatus to preserve memories of people and events so, that they can later be distinguished from each other. Because new cells are formed in the part of the brain, that is needed for pattern separation and movement causes the brain to form new cells, it can be said, that physically more active people perceive life in a more nuanced way. By depression, on the other hand, a person's emotional life loses its shades, he does not perceive everything as full of nuances and his life seems gray and boring.

In addition to physical activity, the formation of new brain cells is also affected by the environment. In fact, since the amount of new brain cells also depends on how much they survive, because fresh brain cells are very fragile, and usually only half of them survive, for example, in animals will survive about 80 percent of new brain cells. So, as a result of movement, more new brain cells are formed and the favorable environment increases the chances, that they will survive.

So walks in the wild or running in the woods work very well for body and mind, both - because we move and because nature is a beautiful and soothing environment.