Apr. 11, 2012 —
Science Daily/Brigham and Women's Hospital
A study by researchers at Brigham and Women's Hospital (BWH) reinforces the finding that too little sleep or sleep patterns that are inconsistent with our body's "internal biological clock" may lead to increased risk of diabetes and obesity. This finding has been seen in short-term lab studies and when observing human subjects via epidemiological studies. However, unlike epidemiological studies, this new study provides support by examining humans in a controlled lab environment over a prolonged period, and altering the timing of sleep, mimicking shift work or recurrent jet lag.

The researchers saw that prolonged sleep restriction with simultaneous circadian disruption decreased the participants' resting metabolic rate. Moreover, during this period, glucose concentrations in the blood increased after meals, because of poor insulin secretion by the pancreas.

According to the researchers, a decreased resting metabolic rate could translate into a yearly weight gain of over 10 pounds if diet and activity are unchanged. Increased glucose concentration and poor insulin secretion could lead to an increased risk for diabetes.

"We think these results support the findings from studies showing that, in people with a pre-diabetic condition, shift workers who stay awake at night are much more likely to progress to full-on diabetes than day workers," said Orfeu M. Buxton, PhD, BWH neuroscientist and lead study author. "Since night workers often have a hard time sleeping during the day, they can face both circadian disruption working at night and insufficient sleep during the day. The evidence is clear that getting enough sleep is important for health, and that sleep should be at night for best effect."
http://www.sciencedaily.com/releases/2012/04/120411144316.htm