"We believe that ultraviolet light has an effect on mood that tanners value," said Steven Feldman, M.D., Ph.D., lead researcher. "This may be creating a reinforcing effect that influences tanning behavior."
The research - involving 14 young adults who regularly used tanning beds -is reported in the July issue of the Journal of the American Academy of Dermatology, which is now available on-line. For six weeks, study participants had tanning sessions on Mondays and Wednesdays in two identical-looking tanning beds. They spend half of each session in one bed and half in the other. There was a key difference in the beds, however - only one used ultraviolet light (UV).
UV light occurs naturally in sunlight and is responsible for the tanning and burning effects of the sun. Artificial UV light is used in tanning beds and sunlamps.
Mood was measured before and after each tanning exposure. The results revealed greater relaxation and lower tension after UV exposure compared to non-UV exposure. The researchers theorize that UV exposure leads to the release of chemicals in the brain called endorphins that are linked to both pain relief and euphoric feelings.
"A more relaxed and less tense mood was reported after UV exposure compared to after non-UV exposure," said Feldman. "We believe these relaxing and reinforcing effects contribute to tanning behavior and may help explain why people choose to tan despite the risks."
During the six-week study, participants had the option of additional tanning on Fridays in either of the beds. Twelve of the subjects chose additional tanning - and for 95 percent of the sessions they chose the UV bed.
"There are probably many factors that influence the choice to tan frequently," said Feldman, a professor of dermatology. "But we found that when subjects are offered tanning beds that differ only in the presence or absence of UV light, they choose the bed with UV light. Moreover, the choice of UV is associated with a sense of greater relaxation."
Feldman said the finding is significant because, like other risky behaviors, it is important to understand why frequent tanners choose the activity. Exposure to UV through tanning has been shown to damage the genetic information in cells and is linked to the development of skin cancer. Despite this, there was a 300 percent increase in the number of indoor tanners in the United States between 1986 and 1996.
Most research into the motives for excessive tanning has focused on effects such as appearance. However, there is some previous evidence supporting a relaxation effect. Laboratory studies have shown a release of endorphins in response to ultraviolet light exposure. And, a survey of college students showed that relaxation was one of the most common reasons identified for tanning.
"Since we didn't measure endorphins, we don't know for sure that these substances are responsible for the phenomenon," said Feldman. "But, our findings suggest a course for future research into why people use tanning beds and the mechanism of mood changes associated with tanning."
The research was funded, in part, by the National Institutes of Health.
Feldman's co-researchers were Anthony Liguori, Ph.D., Michael Kucenic, M.D., Stephen Rapp, Ph.D., Alan Fleischer Jr., M.D., Wei Lang, Ph.D., and Mandeep Kaur, M.D., all with Wake Forest Baptist.
About Wake Forest University Baptist Medical Center: Wake Forest Baptist is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university's School of Medicine. The system comprises 1,282 acute care, psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of "America's Best Hospitals" by U.S. News & World Report.