About a decade ago, Marc Berman — who was a doctoral student at the University of Michigan — ran a study where he sent volunteers on a 50-minute walk through the Nichols Arboretum or through the city streets of Ann Arbor. After, he gave his volunteers a cognitive assessment. Those who walked through the Arb performed about 20% better than their counterparts in memory and attention. They also reported to be in a better mood.

These walks took place year round, from warm days in June to freezing ones in January. But the results stayed the same. In addition, he found that the positive effects were five times more extreme in those diagnosed with clinical depression.

An increase in mood when spending more time in nature can be traced back to our prehistoric roots. The theory is that we respond well to things that are good for us. Back in the day, trees made us happy because they offered shade, protection, and commonly had fruits and nuts. Although we no longer depend on trees for these aspects of survival, it is ingrained in our instincts to be happier when we are around trees. This increase in mood can lower anxiety levels and increase productivity.

But it’s not only the visual aspect of nature that contributes to being less stressed out. Scents can also lower these stress levels. The smell of pine trees has been shown to lower depression and anxiety. In addition, many flowers - like jasmine, lilacs, and roses - have been proven to increase relaxation and decrease stress.

There seems to be an endless amount of studies showing the positive effects of being in nature. According to a study conducted at the University of Essex, the color green makes exercise easier. Exercise is also a proven stress relief. Another study showed that kids with ADHD reported fewer symptoms when they spent time in green outdoor spaces, compared to those who spend time indoors, even though they were doing the same activities.