Sunlight is as important to your body as vitamin C or calcium. And the reason is vitamin D.
When exposed to sunlight, your body manufactures vitamin D, a characteristic that makes this nutrient a hormone as well as a vitamin. More and more research has shown that vitamin D is a critical part of overall health. Not only does it reduce ocular inflammation and help prevent macular degeneration, it has also been shown to boost your immune system and lengthen your telomeres.
This last bit is critical, as research is beginning to show that telomere shortening plays a big role in aging. Telomeres are the end caps of every cell’s DNA. They act like the plastic fittings on the ends of your shoelaces, and keep your DNA strands from fraying.
The longer the telomere, the younger your cells will be. But each time your cells divide, your telomeres get shorter, and shortened telomeres can lead to degenerative conditions.
By working to prevent telomere shortening, vitamin D keeps your body more youthful and vital.
But that’s not all. Vitamin D is also critical for bone and muscle health. On the bone front, it helps you maintain calcium blood levels by increasing the amount of calcium you absorb from food and reducing the amount you lose each day. It also reduces your risk of fracture.
When it comes to muscle health, there is no question of the importance of vitamin D. The hallmarks of vitamin D deficiency include weakness of the proximal muscles (those that attach your limbs and neck to your body), muscle pain and difficulty walking.
Additionally, the vitamin D receptor is activated in muscle tissue, and activating it may produce new protein synthesis in the muscle itself. In fact, observational studies have shown that serum blood levels of vitamin D correlate to muscle strength and/or lower extremity function in seniors.
Given this, it is no surprise that several double-blind, placebo-controlled studies have found that vitamin D supplementation increases muscle strength and balance while also reducing risk of falling in seniors.
Going Beyond Vitamin D
But the benefits of sun exposure don’t start and end with vitamin D. It is widely accepted that exposure to natural outdoor light, at specific hours and for a specific length of time, regulates your biorhythms of waking and sleeping, as well as triggering the release of neurotransmitters such as serotonin that control these functions.
Similarly, exposure to sunlight has traditionally been used to regulate mood, treat fatigue, and reverse depression. In fact, there is a growing body of research that suggests sunlight is also beneficial for adrenal function. Studies have shown that exposure to natural light for one and a half to two hours a day may activate the adrenal glands and support your body’s response to stress.
Get Out in the Sun
There are some real dangers associated with too much sun, but you do need some unprotected exposure to sunlight, ideally every day, to help you from becoming vitamin D deficient.
Aim for 15 to 30 minutes, depending on your skin tone and geographical longitude. The farther north you are and the darker your complexion, the longer your exposure can be. Just don’t exceed 30 minutes unprotected. If you are fair skinned and/or live closer to the equator where the sun’s rays are stronger, 15 minutes is your best bet.
If you can’t get your 15 to 30 minutes outdoors on a consistent basis, consider taking a vitamin D supplement to help harness the sun’s health benefits.
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 Richards JB et al. Higher serum vitamin D concentrations are associated with longer leukocyte telomere length in women. Am J Clin Nutr. 2007;86(5):1420-5.
 Bischoff-Ferrari HA. Relevance of vitamin D in muscle health. Rev Endocr Metab Disord. 2011 Oct 22. [Epub ahead of print.]
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