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Does UVA Exposure Release Endorphins?

We still don't know why tanning feels so good.

Why do we experience a sense of well-being during sunbathing and in tanning beds? Previous research has focused mostly on eye exposure to sunlight and the eye-brain mechanism, but whole-body exposure to UVA light has been shown to raise circulating levels of opioid peptides, which can produce feelings of pleasure.

These researchers randomized 44 healthy volunteers (mean age, 24; 75% women) to UV light exposure in a tanning bed (16 J/cm² for skin type II and 21 J/cm² for skin type III; 35 participants) or to rest in an inactive tanning bed (9 participants). Participants underwent 6 sessions over 3 weeks. The air-conditioned tanning unit emitted mostly UVA radiation but also emitted a small amount of UVB radiation.

Venous blood samples were taken from all participants at baseline, 20 minutes after the first session, and 24 hours after the sixth session. There were no significant differences between exposed participants and controls in mean plasma levels of ß-endorphin immunoreactive material and met-enkephalin (as detected by radioimmunoassay).

Comment: In this small study, which used limited plasma sampling, UVA light exposure did not significantly elevate plasma levels of ß-endorphin and met-enkephalin. However, until our understanding of ß-endorphin fragments improves and we have better assays to measure them, we will be unable to fully assess the relation between UV light-associated psychological well-being and levels of circulating opioids.

— James Ferguson, MD, FRCP

Published in Journal Watch Dermatology January 29, 2003

Citation(s):

Gambichler T et al. Plasma levels of opioid peptides after sunbed exposures. Br J Dermatol 2002 Dec; 147:1207-11.

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