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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Aging, sun exposure, and heart health: What’s the relationship?

Exciting new research explores how decreased nitric oxide functioning, which is associated with aging, increases the risk of cardiovascular disease possibly via decreased vitamin D levels, and other mechanisms.

Increased levels of Vitamin D, produced in the skin from ultraviolet-B radiation in sunlight, is one of the most established health benefits of consistent and safe sun exposure.

Archeological evidence suggests that we evolved to rely on the sun to maintain optimal health. Consequently, researchers are constantly exploring different aspects of sunlight that can contribute to both risks and benefits of sun exposure.

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  About: Jeff Nicklas

Jeff Nicklas was a staff member for the Vitamin D Council from October 2013 to January 2015. He is now pursuing his passion for public health through graduate studies.

7 Responses to Aging, sun exposure, and heart health: What’s the relationship?

  1. mbuck says:


    Is there any indication of how, how long one has to be in the sun for NO release into the blood? Can one release NO all year round or does the effect only occur in the summer?

    I know for D3 synthesis at solar noon at latitude 38 I need to be in the sun 30 45 minutes total, full body, flipping front to back during the session, in order for me to get an estimated 8000 to 12 000 IU. I use a solarmeter 6.2 and a 6.4 for the estimate and have a blood spot test twice a year around the equinoxes.

    The rest of the year I supplement with D3 combined with all co-factors and a range of various nutrients rich in bio-available Mg Se etc.

    My range varies from 59 to 70 ng/ml all year round.


  2. Magic says:


    You are much more scientific than I. I go out in the sun and enjoy it. We have had plenty of it here in Eugene, Oregon this summer. I have been taking 20,000 iu D3 because I feel great. I take more when I don’t feel great which really doesn’t happen.. I have studied this for years. A question I have. If 50,000 units a day seems to help people with MS, why should people be afraid to take what helps them.?

  3. Jeff Nicklas says:


    That is a great question. Researchers have only just discovered the ability for ultraviolet-A to release NO stores in the skin, and there aren’t many definitive answers regarding this interaction.

    A study from earlier this year had participants undergoing ultraviolet-A radiation to mimic 30 minutes of sun exposure at noon on a summer day. This amount of time (20-30 min) was enough to cause a release of NO from the skin.


    In terms of ultraviolet-A (UVA) availability, UVA rays are stronger and have an easier time reaching the Earth’s surface. It is suggested that UVA wavelengths can reach the surface of the Earth, and thus your skin, at most times throughout the year depending on where you live.

    Let me know if you any further questions.


  4. mbuck says:


    Beats me, but then I’m not a med professional, just a self-educated layman. I can say there still a reticence to supplement in many quarters largely because of fears of over dosage and neglecting to keep up up with current research. See Dr. Cannell’s views on this on this site. Then check out Holick, Garland, Vieth, and the growing number of other researchers, and the growing number of recent studies, RCTs, etc.


  5. mbuck says:

    @ Jeff Nicklas,

    I think you’re answered my question.

    If it’s UVA, then sun exposure all year round at my latitude (38 degs) will likely work.

    I know researchers are studying other beneficial effects of sunlight. The observation that in skin, the largest organ of the body, photosynthesis of beneficial compounds takes place, causes me to reflect that plants also expose their largest surfaces, leaves, for similar but different reasons.

    And we know what happens to plants taken out of the sunlight, they begin to wilt.


  6. Rebecca Oshiro says:

    I recently read this paper and while it doesn’t directly answer your question, mbuck, it leads me to believe it happens rather quickly:

    The rapid release of NO• following UVA exposure suggests the existence of latent stores. It is well known that part of the endogenously produced NO• is converted into nitrite (NO2-), nitrate or nitrosothiols. Earlier it was thought that these compounds are inert end products of endogenous NO• metabolism. In 2003 Rodriguez et al.132 demonstrated that in rat vascular tissue NO2- and nitrosothiols, but not nitrate, are converted back to NO• under UVA exposure:
    NO2- + hν → NO• + O•-.

    The action spectra for NO• release from nitrite and from nitrosothiols have a peak at around 335 nm and lie in the range from 310 to 400 nm.132 Human skin and dermal vasculature contains high quantities of NO2- (8.4 µM) and nitrosothiols (2.9 µM), which can be recycled by environmental stimuli, such as UVA radiation, to form NO•.128–130,133 The skin of a human weighs approximately 4 kg and can be considered the largest human storage organ for NO derivatives such nitrite and nitrosothiols.133 Thus, they represent an important alternative non-enzymatic physiological source of biologically active NO•. Healthy human skin contains 25-fold higher concentrations of NO2- than plasma of healthy volunteers.130 It has been demonstrated in human keratinocytes in vitro and in healthy volunteers that UVA exposure induces NO• in concentrations comparable to, or even higher than, those produced enzymatically by NO synthases.12

    The full study can be found here:


    The article details the numerous known benefits of UV radiation beyond vitamin D production.

  7. mbuck says:


    Thanks for the link. Some of this I knew already, but not nearly in as much detail.