In a 2011 study of 128 college runners, researchers found that “surrounding greenness” was an indicator of better athletic performance. Other studies have shown that exercising in nature results in less fatigue, reduced anxiety, less hostility, more positive thoughts, and an overall feeling of invigoration.
Natural settings alleviate directed-attention fatigue (DAF), which occurs when the brain’s prefrontal cortex must constantly manage competing stimuli. DAF can cause impatience and irritability. Gazing at clouds and trees restores both mood and cognitive function.
Running on natural surfaces, specifically grass, is 15 to 35 percent easier on your joints—especially your knees—than running on pavement and also lessens the impact on the plantar fascia, the sensitive tissue that supports your arch. The shock absorption also makes your muscles work harder, so you get a better workout.
When you’re relaxing in nature, your adrenal cortex produces less of the hormone cortisol, which activates the body’s stress response. Prolonged periods of stress can also shrink the hippocampus, which is where we form and store memories. By contrast, less stress enhances neuroplasticity, the brain’s ability to form new connections.