Spending time around trees and looking at trees reduces stress, lowers blood pressure, and improves mood. Numerous studies show that exercising in forests and simply sitting looking at trees reduces blood pressure and the stress-related hormones cortisol and adrenaline.

In general, the outdoors has a calming effect on us, and it has to do with the fresh air we're inhaling. Breathing is linked to the production of stress hormones. When breathing rapidly, our sympathetic nervous system is activated, and the body is energized for a "fight or flight" response.

What you are seeing, hearing, and experiencing at any moment changes your mood and how your nervous, endocrine, and immune systems are working.