Out-of-sync days throw heart and metabolism out of whack

Sleeping during the day and staying awake at night can lead to heart and metabolic problems, even after just a few days of the out-of-sync schedule, a new study reports. The results, published online March 2 in Proceedings of the National Academy of Sciences, may help explain the high rates of heart disease, diabetes and obesity among people who work the graveyard shift.

“The problems of shift work affect so many people, but there are very few studies that address the underlying mechanisms,” comments Eve Van Cauter, a sleep researcher at the University of Chicago. “This is what [the researchers] have done, and elegantly so.”

Based on Bureau of Labor Statistics data, the researchers estimate that 8.6 million people in the United States are shift workers.