Having a strong immune system is vital to a healthy life. We have evolved an incredible defense system to help keep everything from the common cold to cancer at bay and when our defenses are down, our health is at risk. Interacting with nature can be instrumental in keeping our immunity strong and our lives invigorated.
There are several factors that play a role in having a strong immune system, all of which nature can help support. Factors such as having enough sleep, exercise, a good diet, no to little stress and feeling part of a caring community.
Aside from the evening silence that nature innately provides for a restful night, there is a growing body of research which also suggests that spending time in nature may improve sleep by resetting our internal clocks to a natural sleep cycle. Aligning with the natural sunlight of the day has a direct impact on our melatonin levels which is an essential hormone that is pivotal to good sleep. A ground breaking study also suggests that two hours of forest walking or Forest Bathing increased duration of sleep and self-reported sleep quality amongst participants. It is hard to deny that having enough good quality sleep with nature’s help supports our immune functions.
Exercise is key to having a good immune system; nature supports and encourages being active in an expansive and softly fascinating environment. It may not just be exercise, but ‘green exercise’ that most benefits our health. There is a recent and fascinating study that shows that the color green, as a primitive feature of visual sensation, has a contributory effect toward positive green exercise outcomes such as having less tension and improved mood.
There are still relatively few studies of the effects of nutrition on the immune system and even fewer studies that tie the effects of nutrition directly to the development of diseases but one can use common sense: Eating good food from nature makes for a healthy body. To state the obvious and in the most general of terms, food comes from nature and the more we consume food that is closer to the source without the use of man made chemicals and the fresher the food is, the better our health and immune systems can be.
Being in nature and exposured to nature imagery has been shown to reduce our stress levels in quantifiable ways. Measurements of stress hormones, respiration, heart rate, and sweating suggest that short doses of nature or even pictures of the natural world can calm people down. We all have experienced the state of calm that washes over us in a forest or on a beach. Your immune system thanks you.
Being part of a caring community increases our social support and studies show may contribute to our health and longevity. It’s not clear why yet, but one theory holds that people who enjoy close relationships with family and friends receive emotional support that indirectly helps to sustain their immunity at times of chronic stress and crisis. Being part of a community of humans is wonderful, but let’s not forget the sense of belonging to nature as a whole. While we strengthen our connection and relationships to nature and to the communities of wildlife and plants, we may also be building a life enhancing social net that can contribute to our good health. More research is needed to support this latter theory.
For your health and wellbeing, spend time thinking about, looking at and being in nature. Your immune system will thank you.
Fourteen healthy male participants with normal color vision were recruited for this study where participants exercised on a stationary bike while looking at a simulated natural environment. they were required to watch a video of 1. a “green outdoor environment” cycling course with greenery, 2. the same footage presented achromatically as blank and white, and 3. The same footage using a red filter. Participants were required to rest between video trials until their cardiorespiratory measures had returned to post warm-up levels. Heart rate, oxygen uptake, respiratory exchange ratio, and ratings of perceived exertion were recorded during the last 30 s of each 5-min cycling trial. This was the first study to show that the color green, as a primitive feature of visual sensation, has a contributory effect toward positive green exercise outcomes.
In a study in Japan by Q Li and colleagues, 12 healthy men between the ages of 37 and 55 took a three-day, two-night trip to the forest. On the first day, the men spent two hours in the afternoon walking in the forest. On the second day, they walked in the forest for two hours in the morning and two hours in the afternoon. Blood samples tested on days two and three showed that in 11 of the 12 men there was a 50 percent increase in natural killer cells. NK cells play a major role in the host-rejection of both tumours and virally infected cells. Further studies have shown that these positive immune benefits can last up to a month after a visit to the woods.