There are many benefits of sunlight on the human body, there are, however, also some downsides that are worth noting.
The summer is a wonderful time of the year. It allows us to spend time outdoors enjoying the delights that nature has to offer. For the majority of us, it is the time that we get the most exposure to sunlight. There are both pros and cons to this exposure, however. It is important to find a balance between protection from the potential dangers of UV rays, and the known health benefits that come from sunlight.
Vitamin D is a fat-soluble essential vitamin that plays many important roles in the body. In addition to maintaining bone health, vitamin D can protect against heart disease, diabetes, and cancers of the breast, prostate, and colon. Vitamin D is necessary for healthy immune function and may reduce inflammation, pain, depression, and sleep. Vitamin D also helps with the absorption of other key nutrients such as calcium, iron, magnesium, phosphate, and zinc.
Known as the sunshine vitamin, the body can synthesize vitamin D3 (cholecalciferol) in the skin from a cholesterol precursor when exposed to adequate UVB (ultraviolet B) rays. Vitamin D synthesis in the body depends on multiple factors including:
- Time of day
- Length of sun exposure
- Cloud and smog cover
- Skin pigment
- Body fat
- Usage of sunscreens
In order to synthesize vitamin D, you need UVB sunlight between 290 and 300 nm. This only occurs when the UV index is above 3, which is not consistent outside of the sunbelt. This means that if you live 37 degrees north of the equator (north of San Francisco, St. Louis, and Richmond in the U.S.) or 37 degrees south of the equator, you’re probably not getting enough sun exposure year-round. It also means that summer is a great time to catch up on some rays.
Beyond a certain point, however, you will get no further benefit from the sun. Vitamin D production will not continue once your body has produced what it needs. Further unprotected exposure to the sun at this point could be harmful.
Melatonin and Serotonin
A humans natural rhythm is set for them to be outside during the sunshine and asleep when it is dark. As well as producing vitamin D, exposure to sunlight helps us regulate Melatonin production, which influences sleep cycles.
Melatonin also helps lower the harmful effects of UV rays on our skin. Serotonin, a neurotransmitter related to mood, is also affected by exposure to sunlight. Getting plenty of sunlight during the day, and sleeping in complete darkness has huge benefits to sleep, energy levels and mood.
Skin Aging, Sunburn, and Skin Cancer
Despite the benefits of exposure to sunlight, UV radiation from the sun can also have harmful effects, contributing to skin damage including:
- Skin cancer
Skin cancer is the most common cancer worldwide, and the three main forms of skin cancer (melanoma, basal cell carcinoma, and squamous cell carcinoma) are largely attributed to excess UV radiation.
It is therefore important that we protect ourselves whilst still getting all of the benefits the sun has to offer.
The following links contain some more important information on the benefits of sunlight, as well as the downsides.