Working Nights Can Impair Glucose Tolerance

A new study has found that people who perform work on night shifts may have impaired glucose tolerance, putting them at an increased risk of type 2 diabetes.

The study was composed of 13 healthy adults who did not have a significant shift work history. Participants completed two, eight day, shifts which included one day and one night work. They ate a common, standardized meal so that proper serum glucose and insulin responses could be assessed. Participants who worked the day shift ate at 8 a.m. and those that worked the night shift ate at 8 p.m. and were required to eat their entire meal within 20 minutes. Initially a fasting blood glucose level was taken and then post prandial levels were taken every 10 minutes for 9 times and then every 30 minutes for 3 times.

Researchers found that workers on the night time shift had a 16 percent higher peak glucose level than workers on a day time shift. Lead author Christopher Morris, PhD, of the Program of the Division of Sleep medicine at Brigham & Women’s Hospital and Harvard Medical School, said, "It is surprising that just a single night shift can significantly impair glucose tolerance and increase insulin levels." "These findings are important because they demonstrate, under highly-controlled lab conditions, that acute exposure to night work impairs glucose tolerance. Chronic impaired glucose tolerance is likely to lead to type 2 diabetes." According to the authors, 8.6 million Americans perform work at night.

American Academy of Sleep Medicine (2013, June 3)