Playing tag outside is the perfect human sport. Children zig zag side-to-side, breathless, in the clean outdoor air; the game is both joyful and competitive. In contrast, a hike through nature creates a calm experience that many people find akin to meditation. Our bodies must concentrate to manage uneven terrain, and our minds delight in absorbing the greenery and the sky above.

Green exercise is the term used to describe activity in the presence of nature, or exercise that happens outdoors. We want to be outside, and we want our children to play outside. This can be a conscious decision based on our understanding of how it affects physical, mental, and emotional states, or it may just be what many of us instinctively do.

Studies show that exercising outdoors is healthy for our physical bodies. Vitamin D is necessary for bone health and immune function, and decreases cancer risk. While of course outdoor athletes must protect from excessive sun exposure, sunlight is necessary for many biological functions. Every few years we understand a bit more about sunlight’s advantages. For example, it was just recently understood that outdoor sunlight exposure prevents myopia progression in children via light-induced retinal dopamine.12 In addition, outdoor terrain provides unique challenges to our gait that enhance balance, which is imperative to long-term health. Outdoor air, especially in natural areas, is less likely to be polluted than indoor air. Of course consistent exercise, regardless of location, helps lower BMI, lipids, and cardiovascular risk factors; because outdoor exercise feels more like play than a chore, people stick to it!

Elevated self-esteem and mood are important, and well-studied, emotional health benefits of exercising outside.3 Sunlight increases our serotonin on bright and sunny days, which elevates mood. The Japanese term Shinrin-yoku or “forest bathing” has been shown to significantly decrease cortisol levels in subjects who spend time in nature.45 Living near parks or green areas statistically reduces the risk of depression and suicidality in urban settings. 6 Many of us intuitively know how happy we or our children feel after a lovely day outside: walking the beach or playing in the park.

An excellent book for the parents of my pediatric patients on how exercise affects intellectual development is the classic 2013 book Spark by John Ratey, M.D. He enumerates the data on how physical education classes and time playing outside during recess help schools increase test scores, decrease individual ADD symptoms, and increase learning potential. On the opposite end of the life spectrum, studies consistently show that exercise reduces risk factors for dementia.

As John Muir said, “Of all the paths you take in life, make sure some of them are dirt.” My hope for you, your children, and the children in your neighborhood is that you move and play outside this spring. Perhaps you might start a game of catch in the yard, grab a friend for a hike in the woods, or play a feisty game of tag.