If you must sunbathe, stick to mornings

摘要

WANT to top up your tan? Then aim to catch some rays early in the day when your circadian rhythms might make It safer. "If you really must go to a tanning booth, do it in the morning," says Aziz Sancar of the University of North Carolina at Chapel Hill. His team found that a mouse's circadian rhythms impede its ability to repair DNA damage caused by UV radiation in the morning. Because mice are nocturnal, you would expect the opposite in people. After three UVB sessions a week for 25 weeks, mice placed under a UV lamp only in the early morning had five times as many tumours as mice exposed 12 hours later.