Serotonin and Sunshine

“Sunshine, on my shoulders, makes me happy.”

-John Denver

When I was a young boy my family spent our vacation time on the road, traveling in a small R.V., exploring and camping throughout the U.S.. While doing so, our primary source of entertainment for those often long drives was listening to an old 8-track player. John Denver’s Greatest Hits was a family favorite and there is a lesson to be learned from this simple and classic lyric that revolves around the joy found from being outdoors.

As a child I recognized the truth regarding his words about sunshine. It did make me happy. It was good for me. However, aside from that intuitive internal agreement, I didn’t give it much more thought.

Exposure to sunlight is a necessary component to living a healthy life for a variety of reasons. Apart from being the source for nearly all energy and thus life on the planet, it has direct personal effects that are important for every one of us. Sunlight is essential in the production of vitamin D. Vitamin D, in turn, is important for the absorption of calcium and thus the strength and health of our bones and teeth. Sunlight has also been shown to be effective in assisting the management of certain skin conditions such as psoriasis and fungal rashes. Certainly as interesting, is it’s role in happiness.

The 5th century Greek physician Hippocrates, considered the father of western medicine, wrote of ‘melancholia’, describing it as “an aversion to food, despondency, sleeplessness, irritability, restlessness” and “fear or depression that is prolonged.” Those early writings attributed this melancholia to the accumulation of black bile which was thought to be cold and dry, and was paired with the season of autumn. Prescribed remedy? A little sunshine on your shoulders sounds about right.

Sunshine and Serotonin 3 Sunlight is involved in the balancing of hormones that affect mood. But why? Some of it appears to be related to the neurotransmitter serotonin. SSRI’s (Selective Serotonin Reuptake Inhibitors) are the mainstay for the pharmacologic treatment of depression, and they work by elevating the levels of serotonin in the body. Why this is effective in alleviating depression remains uncertain, however what has also been established is that serotonin and sunlight go hand in hand.

Regardless of the season, the turnover of serotonin in the brain has been shown to be affected by the amount of sunlight on any given day. The levels of serotonin are higher on bright days than on overcast or cloudy ones, and its production in the brain is directly related to the duration of bright sunlight. Further evidence for the notion that changes in the release of serotonin by the brain underlie mood seasonality and seasonal affective disorder, and underlying the sun’s role in this relationship.

It is important to note that, as with much in life, there exists a need for balance and moderation. Too much sun can be a bad thing, specifically due to the relationship between UV B radiation and skin cancer, so it is important to use frequent and liberal application of sunscreen with an SPF (Sun Protection Factor) of 15 or higher when out in the sun for extended periods. However, try to get at least 30 minutes of sun exposure each day (two hours has been proposed to maintain balanced serotonin levels). Take a morning or late afternoon walk, sit outside during lunch breaks or plan outdoor activities on the weekends. And don’t forget to protect your skin by using sun screen.

So as we head into another spring, remember the words of Walt Whitman who said, “Keep your face always toward the sunshine - and shadows will fall behind you.” Or just keep it on your shoulders.