The Health Edge: Light Quality and Health

In this rebroadcast episode of The Health Edge John and mark look at the connection between quality light exposure and health. They introduce the notion that the public health message of fearing sunlight exposure may be having the opposite effect of what was intended. The biologic effects of increasing junk light exposure may be profound for many!

4 thoughts on “The Health Edge: Light Quality and Health

  1. Brittany

    I’ve been wondering this for a while, but is there benefit for the blind to continue to get sun exposure and could this help with the “non-24” disorder? If their retinas are not working for vision, do they still process the sun light?

    • The majority of blind people have some light perception and circadian rhythms that are synchronized to a 24-hour day-night cycle as in the sighted. For a totally blind individual with Non-24, their visual disorder or lack of eyes prevents the light-dark cycle from synchronizing their internal body clock to the 24-hour day-night cycle. Often, the sleep disturbance is less clear, with more subtle changes in the timing of sleep, or may even look normal, even though the circadian clock is still not synchronized with the 24-hour cycle. Only an assessment of a strong biochemical circadian rhythm, such as the melatonin or cortisol rhythm, can confirm whether a non-24-hour rhythm is absent or present.
      In addition, sunlight exposure has many benefits as mediated through skin exposure e.g. nitric oxide production, vitamin D production, mitochondrial bioenergetics, biotransformation, etc. Thank you for listening to The Health Edge!

    • Hi jessica. I think about light from a couple of perspectives. As the day-night cycle changes over the autumn-winter season, a full-spectrum light box (full spectrum implies all the colors of the rainbow are present…optic folks refer to color rendering index of over 97%, 100% being that of sunshine) is important. The second attribute of a good quality light box is the intensity of the light (lux or lumen) and most of the studies in seasonal affective disorder suggest 10,000 lux to be a therapeutic threshold. There are many good brands that meet these criteria. I like Northern Lights ( though you can find many brands that meet these crieria.

      A separate issue is vitamin D which requires UVB light frequency. This is a specific “band” of light in the UV range that stimulates vitamin D production (5-10″/day). I use Sperti ( because it has been studied and published (Michael Hollick MD, PhD at Boston University) and shown to measurably raise serum Vitamin D levels with regular use.

      I hope this is helpful. Be well.

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