Humans Need Sun
Preventing melanoma does not mean avoiding the sun at all times; getting outdoors is essential to a healthy lifestyle. Practicing responsible sun exposure allows you to experience the many benefits of sun exposure while protecting yourself from the harmful UV radiation the sun emits. For more information on practicing responsible sun exposure click here.
Vitamin D production occurs in one's body from UVB radiation exposure. There are multiple forms of vitamin D, but the one naturally produced by sun exposure is vitamin D3. It is important to note that one does not need to burn his/her skin in order to reap the benefit of vitamin D3 from sun exposure. In the medical community, there is disagreement over whether or not ingestible vitamin D2/D3 supplements confer the same benefits as naturally-produced vitamin D3. A large-scale clinical study currently taking place in Australia is attempting to discern the relative efficacy of vitamin D3 supplements; this study is called the Sun Exposure and Vitamin D Supplementation (SEDS) Study. Although it is currently unclear whether or not vitamin D supplements offer the same benefits of sun-induced vitamin D3 production, it is widely understood that vitamin D deficiency is a risk factor for a plethora of diseases including tuberculosis, multiple sclerosis, rickets, osteomalacia, and various forms of cancer. Vitamin D is so important to immune system health that a serum vitamin D level of 40 ng/ml decreases cancer risk by 67%, when compared with levels of 20 ng/ml or less. Serum vitamin D levels can be obtained through a simple blood test.
Circadian rhythm is similar to a biological clock-- it describes repetitive daily behaviors, including sleep schedules. Exposure to sunlight helps anchor one's circadian rhythm which improves sleep quality, leading to multiple health benefits besides feeling well-rested. An interesting relationship between vitamin D levels and obstructive sleep apnea exists. Research proves that risk of obstructive sleep apnea is associated with low vitamin D levels; considering that vitamin D deficiency is a surrogate marker for sun avoidance, it is not surprising that one study from Dublin, Ireland reported 98% of patients diagnosed with sleep apnea also had vitamin D deficiency.
When skin is exposed to sunlight, nitrates are converted into a potent vasodilator called nitric oxide. A vasodilator increases the diameter of blood vessels, allowing blood to flow at lower pressures. Therefore, higher levels of nitric oxide are associated with a decreased risk for heart attacks and strokes. Recent studies have shown an inverse relationship between the amount of sun exposure one receives and his/her blood pressure. Regions near the equator have populations with lower blood pressures than regions farther from the equator. However, equatorial regions also have higher melanoma incidences than regions in northern/southern latitudes. This fact demonstrates the importance of responsible sun exposure.
THE SUN FEELS GOOD
Studies have shown that the sun induces the production of dopamine and serotonin, two chemicals associated with feelings of happiness and well-being. Research indicates that the sun may directly stimulate serotonin production through the skin, and retina (through the eye). There is also evidence linking sunlight exposure to increased levels of dopamine. The production of serotonin and dopamine from sunlight exposure may explain addictive sun tanning.