Exposure to ultraviolet (UV) radiation from tanning machines stimulates the “rewards center” in the brains of frequent UV tanners, which could cause tanning addiction, according to a new study in Addiction Biology. When activated, the rewards center releases feel-good chemicals, which “could reinforce the tanning behavior, encouraging excessive tanning,” said Heidi T. Jacobe, MD, study coauthor and Assistant Professor of Dermatology at the University of Texas Southwestern Medical Center at Dallas.
Researchers studied seven volunteers, all of whom tanned indoors two to three times a week and reported some signs of UV light addiction, such as having difficulty limiting their tanning. During two 10-minute sessions, volunteers lay beneath a tanning canopy, receiving either real UV or “sham” UV (light emitted by a tanning lamp, from which the actual UV radiation had been filtered out). Each subject received one real and one “sham” UV session, and immediately after each, subjects applied a self-tanner to help prevent them from determining if they had had an actual UV tanning session.
“Subjects did not know whether they were exposed to real or ‘sham’ UV tanning rays, yet reported greater satisfaction and decreased desire to tan only when they were exposed to the real UV tanning rays,” Jacobe said. “This implies a biological effect of tanning rays on the brain.” This was supported by follow-up brain imaging studies in the same patients — subjects were injected with a solution that allowed researchers to identify telltale signs of rewards center activity (increased blood flow in specific areas of the brain) in a scan conducted 90 minutes after each tanning session. The real UV radiation activated the rewards center more significantly than the sham UV, prompting feelings of well-being — and possibly more UV tanning later. The data reinforced earlier research showing that UV triggers the body’s release of opioid-like endorphins, chemicals that relieve pain and generate pleasurable feelings.
Both before and immediately after the tanning session, before they could see their skin color, subjects were asked about their desire to tan. The regular tanners exposed to real UV light all reported a marked decrease in the desire to tan.
UV radiation is associated with about 90 percent of all skin cancers. Indoor tanners increase their risk of melanoma, the deadliest form of skin cancer, by 74 percent. They are also 2.5 times more likely to develop squamous cell carcinoma and 1.5 times more likely to develop basal cell carcinoma.