Rotating Night Shifts Hurt the Heart
Shift work has long been known to create problems in areas like sleep, diet or driving safety. But it seems that rotating shift work (that is, working night hours only on occasion) adds an additional health risk.
In a new study, nurses who worked at least 3 nights per month were more likely to develop heart problems over the next 24 years than nurses who stuck to daytime shifts.
Researchers from Harvard Medical School and Brigham and Women's Hospital in Boston used data from more than 189,000 women who were participating in the Nurses' Health Study (NHS) in 1988 and 1989.
The women entered the studies between the ages of 25 and 55. At the start, none of them had coronary heart disease. Over the years, there were nearly 11,000 cases of coronary heart disease problems -- heart attacks, chest pain and bypass surgeries.
Heart problems increased with the number of years women spent covering night shifts: Risk of coronary heart disease was 12% higher in nurses who worked night shifts for less than 5 years, 19% higher in those who worked night shifts for 5 to 9 years, and 27% higher in nurses who worked nights for at least 10 years.
There is one piece of good news here -- the risk of coronary heart disease came back down as women quit working night shifts or retired. Those with at least 10 years of rotating night shifts had a 27% increased risk of coronary heart disease during the first half of the follow-up period, but only a 10% increased risk during the second half.