Working the graveyard shift can be pretty miserable. And not just because you're awake when friends and family are asleep and you are desperately to sleep when they're awake. There's good evidence that regular night shift work can also be a serious health challenge. You face an increased risk of heart attack, stroke, and even certain types of cancers.

Now a new study is showing this seems to be connected to an important natural hormone you may have heard of - melatonin. Melatonin helps regulate our sleep and wake cycles - our circadian rhythms. But Dr. Parveen Bhatti, an epidemiologist at the Fred Hutchinson Cancer Research Center, as well as at the University of Washington in Seattle, has found that it also may be important for helping our cells deal with the kind of damage that can lead to cancer.

Paper in the journal Occupational and Environmental Medicine: Oxidative DNA damage during night shift work