by Aditi Gupta
It’s almost summer! After a long, chilly winter (and an almost equally frigid spring), the weather is finally taking a turn. As the air gets warmer and the plants get greener, it’s important to make the time to head outside and get some fresh air. We often throw around phrases about how going outside makes us healthier or improves our overall mood. But what’s the science behind these claims?
Evolutionarily speaking, the human body and mind have always flourished in the great outdoors. The term “biophilia” was initially coined by biologist and ecologist Edward O. Wilson as a descriptor for humanity’s affinity for the natural world [1]. From this word was born the biophilia hypothesis, or the idea that humans possess an innate tendency to seek out connections with nature. This concept has since been broken down into several major theories, the most important of which is the Stress Reduction Theory, or the idea that spending time in nature leads to the activation of the parasympathetic nervous system. This causes a decline in stress and autonomic arousal and influences positive emotions [2].
These theories aren’t simply hypothetical statements; studies have demonstrated the concrete physical impacts that spending time outside has on our bodies and minds. Being outside leads to a decrease in cortisol levels, reducing stress. There is also a significant reduction in heart rates and muscle tension [3]. Sunlight energizes the T cells necessary to fight off infections [4].
Melatonin is a hormone produced in the skin upon exposure to sunlight. Melatonin aids with the regulation of your circadian rhythm, which is your body’s 24-hour sleep cycle. Your circadian rhythm is most sensitive to light one hour after waking up. Exposing your skin to sunlight during this time can help you feel more refreshed and energized in the morning [5].
Sunlight triggers the production of Vitamin D when its ultraviolet B (UVB) light makes contact with your skin. Vitamin D promotes the absorption of calcium in the gut and regulates calcium and phosphate concentrations, enabling proper bone mineralization. It reduces inflammation, regulates cell growth, and boosts immune function [6]. Melanin, or the pigment in your skin, absorbs the sun’s UV rays. Depending on the amount of melanin in your skin, it can take anywhere from 10 to 20 minutes per day in the summertime to get your recommended daily dose of Vitamin D. The best time to go out is around midday [7].
It’s important, however, to stay sun safe. Make sure to wear broad-spectrum sunscreen with an SPF of at least 30 and bring a wide-brimmed hat along with you [8]. A common misconception is that wearing sunscreen prevents sunlight from making direct contact with your skin, obstructing Vitamin D production. In actuality, most sunscreens do not block out all of the sun’s UVB light, meaning that Vitamin D production is not negatively impacted [9].
Venturing into the outdoors is an important first step. Once you find yourself bathing in the sunlight, you might be encouraged to engage in different forms of physical activity. This could be anything— taking a walk, playing a sport, doing some yoga. The most important thing is to get your body moving in a way you enjoy. Exercise has been linked to reduced anxiety and depression, as well as a general increase in body and muscle strength. Exercise also simply makes us happier; it stimulates a rush of adrenaline and an increase in dopamine [10].
The simple sensory experiences of the outdoors have an insurmountable positive impact on your mental health. From the sweet smell of flowers to the melodious sound of the birds, nature can serve as a refuge of sorts, a respite from the emotional chaos of everyday life. By simply being outside, you’re taking positive steps toward improving your physical and mental health.
Take a moment, no matter how brief, to step outside. Look around at the greenery. Take a deep breath. Inhale the delightful aroma of the flora and fauna. Maybe do some gardening, or take a light stroll around the neighborhood. Revel in the exquisite feeling of the warmth on your skin. Get out there, and have a great time!
[2] Associations between Nature Exposure and Health: A Review of the Evidence
[3] The wellness benefits of the great outdoors
[4] Sunlight Offers Surprise Benefit – It Energizes Infection Fighting T Cells.
[5] Effect of Daylight on Melatonin
[6] Vitamin D Fact Sheet for Health Professionals.
[8] Spend Time Outside and Stay Sun-safe