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.
In mice, "handyman" proteins that fix DNA damaged by UV seem to be more active in the evening. Mice bred to have no circadian rhythms were as likely to develop cancer in the morning as in the evening (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1115249108).
Asthma and heart attacks are also more prevalent at specific times of the day, probably because circadian rhythms affect the activity of cells.
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Only subscribers may leave comments on this article. Please log in.
Only personal subscribers may leave comments on this article
Subscribe now to comment.
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.
127 hours 127 hours true grit serena williams the falling man the falling man mermaid
কোন মন্তব্য নেই:
একটি মন্তব্য পোস্ট করুন