Yes, some studies have suggested that working night owl shifts for a long period of time can shorten your life by a significant amount - possibly years. Loneli

Yes, some studies have suggested that working night owl shifts for a long period of time can shorten your life by a significant amount - possibly years. Loneliness, poor eating habits, and hormone changes were all cited as possible reasons why this might be true. Night shift workers also tend to exercise less, and are more likely to run sleep deficits. A couple of the studies I've read said hormone changes can be permanent in those who worked nights for 5+ years. (Melatonin is the obvious hormone affected, but there were other hormone changes as well.) The fact that many people are unable to stay on a nocturnal schedule, and switch back and forth between days and nights (to see friends and family on weekends, perhaps) makes it even worse, health-wise. The changes are stressful on your body. Most of the studies had participants that were probably quite unhappy about their late shifts, but had to do so out of necessity and not choice. [And they may have also picked up fast food on their way to work every night, for all I know.] So...if you're more productive and happier at night - and you eat properly and exercise - I guess you would only have to worry about the hormone changes...? It's been 5-6 years since I've actively monitored the research, so I'm not sure if there have been any major new findings recently. Check Medline or something.