show we have a different internal experience when we are exposed to nature . These experiences contribute to better mental and physical health in the short and long term .
A 2007 British study showed a walk in nature reduced depression in 71 percent of the participants . 2 That matches up with Japanese research into the practice of shinrin-yoku , which can be translated as “ forest bathing ,” or immersion in a wooded environment . Studies have shown that walking in the woods lowers levels of the stress hormones cortisol , adrenaline , and noradrenaline , boosting immunity and mood . It also reduces heart rate , lowers blood pressure , improves sleep , and increases anticancer protein levels . 3
Eva M . Selhub and Alan C . Logan have pointed out in their book Your Brain on Nature that the Victorians sent those with “ nervous conditions ” or tuberculosis to sanitariums . These facilities were typically located in pine forests , as evergreen trees were believed to emit something into the air that promoted healing . As it turns out , these claims were not the mere invention of imaginative promoters of sanitariums . Selhub and Logan note , “ Natural chemicals secreted by evergreen trees , collectively known as phytoncide , have also been associated with improvements in the activity of our frontline immune defenders .” 4 The air in natural areas , especially in forests or near moving waters such as rivers , tends to have a very high concentration of negative ions , known to increase levels of the mood-boosting neurotransmitter serotonin . These types of ions also are associated with a sense of greater vitality , and they reduce depression , fatigue , and stress . 5 Breathing them in is easy to do when we are outdoors in nature .
Touching soil , or perhaps just being near it and breathing it in to some degree , benefits health , too . An increasing amount of research is showing a connection between microbes , encountered when outdoors , and a healthy gut colony of organisms that contributes to digestive health and even positive moods and protection from depression and anxiety . Dirt puts us in contact with microorganisms that establish their home in our digestive system .
Gardening is one outdoor activity known to have many health benefits , including reduction of physical pain and stress , improved mental wellness , increased physical fitness , increased social contact and sense of community , and greater consumption of fruits and vegetables .
As David Perlmutter , MD , wrote in his book Brain Maker : “ The microbiome is dynamic . It ’ s ever-changing in response to our environment — the air we breathe , the people we touch , the drugs we take , the dirt and germs we encounter , the things we consume , and even the thoughts we have . Just as food gives our bodies information , so does our gut bacteria speak to our DNA , our biology , and ultimately , our longevity .” 6 A healthy colony of microbes in our gut serves to promote our immunity as well as healthy cognitive abilities and emotional well being .
Gardening is one outdoor activity known to have many health benefits , including reduction of physical pain and stress , improved mental wellness , increased physical fitness , increased social contact and sense of community , and greater consumption of fruits and vegetables . 7 In a garden , you are exposed to sunlight , needed for the production of vitamin D and serotonin . Both affect mood , reducing the risk of depression . Most of our serotonin , a neurotransmitter that contributes to a sense of contentment and happiness , is produced not in the brain , where it is used , but in our digestive system , where microorganisms from the environment live . It makes sense that being in the sunlight , touching dirt , and getting physical activity could improve depression and anxiety . Then too , planting , weeding , and harvesting vegetables in a garden offers the health benefit of greater accessibility to foods known to promote health .