April 12, 2012
Disrupted Sleep Schedules Increase Incidences Of Obesity And Diabetes
Researchers at Brigham and Women´s Hospital released a new study this week showing strong correlations with interrupted sleep/wake cycles and the onset of obesity and type 2 diabetes, writes Carolyn Y. Johnson for the Boston Globe.
Twenty-one healthy participants started with getting optimal sleep (approximately 10 hours per night). This was followed by three weeks of 5.6 hours of sleep per 24-hour period and with sleep occurring at all times of day and night, thereby simulating the schedule of rotating shift workers.Thus, during this period, there were many days when participants were trying to sleep at unusual times within their internal circadian cycle–the body´s “internal biological clock” that regulates sleep-wake and many other processes within our bodies. The study closed with the participants having nine nights of recovery sleep at the usual time.
During this part of the study, sugar levels in the blood were “significantly increased” immediately after a meal and during “fasting” parts of the day. The researchers showed that the hormone that lower levels of insulin - the hormone that normally controls blood sugar - were produced.
Three of the participants had sugar levels which stayed so high after their meals they were classified as “pre-diabetic”. They also highlighted a risk of putting on weight as the body slowed down.
A slowed metabolic rate was observed with the irregular, restricted sleep schedule that, if sustained over an entire year with no other changes in the person´s routine and diet, would amount to more than 12 pounds of weight gain.
Orfeu Buxton, assistant professor of medicine at Harvard Medical School and a neuroscientist at Brigham, who led the research explains, “Getting adequate sleep is what we´re calling one of the three pillars of health: sleep, diet, and exercise go well together, and they interact. If you don´t get enough sleep, it´s hard to get enough exercise.”
“If you´re not getting enough sleep, people eat more food. That causes them to gain weight and make inappropriate food choices -- sugary treats and snacks.”
Kathryn Reid, a research assistant professor of neurology at the Feinberg School of Medicine at Northwestern University, who was not involved in the study, was surprised that the age of the participants did not seem to make a difference in how people´s health was affected by sleep. Half of the participants were in their 20s and half were in their late 50s or early 60s.
Reid told Johnson that might be because the people in the study were healthy, while many people who experience shortened and disrupted sleep are shift workers with underlying health problems.
Future questions, she said, will be to understand the health effects of disrupted sleep on that population and to learn what interventions might help metabolism bounce back more effectively, writes James Gallagher, health and science reporter for BBC News.
Dr. Matthew Hobbs, head of research at Diabetes UK, concluded by saying, “This is an interesting study which shows that under extreme conditions involving sleep deprivation and ℠tricking´ the body clock, participants produced less insulin and therefore had higher blood glucose levels then when they were able to sleep normally and live according to normal daily rhythms.”