What a Lack of Sleep Does to Metabolism

by | November 5, 2012 at 12:22 PM | Health

This article was originally published on TheDoctorWillSeeYouNow.com

By Esther Entin, M.D.

Want to lose weight and reduce your chance of diabetes? Go to bed a little earlier and get a full night’s sleep. We are finding that sleep is not just important for recharging your body. It helps keep your metabolism functioning at peak performance. Too little sleep causes a decline in insulin sensitivity, according to a recent study. This means that our growing waistlines are not always or only about too much eating; for many, they are a reflection of too little sleeping.

People who routinely get too little sleep have an increased risk for insulin resistance, (a precursor to diabetes), obesity, and type 2 diabetes.

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Researchers at the University of Chicago decided to examine what actually happens to insulin’s activity when people don’t get enough sleep. They tested healthy young adults who were not overweight and did not have a history of chronic diseases and divided them into two groups. One group slept for 8.5 hours for four consecutive nights, and the other was restricted to 4.5 hours of sleep for the same four nights. Both groups ate the same number and type of calories.

“When the fat cells don’t respond normally to insulin, their ability to take up and store glucose, fatty acids and amino acids is impaired. This causes increases in blood sugar and lipid levels to abnormal levels and contributes to the development of the metabolic syndrome.”

Following the four nights, the researchers took tiny samples of fat tissue from just under the skin of the people in both groups. This subcutaneous fat tissue was chosen because it is a very important site of insulin action and influences how the body burns energy. It also is key to how this energy balance is communicated to the brain, telling the body when glucose (sugar) should be stored, and when it should be used to provide immediate energy.

Sleep deprivation caused a 30% decline in the insulin sensitivity of fat cells of the healthy, lean young adults in the 4.5 hour-sleep group compared to the adults who slept a normal 8.5 hours. The body’s insulin sensitivity paralleled this impaired cellular insulin sensitivity.

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A body-wide decline in insulin sensitivity has potentially significant implications for metabolic health. When the fat cells don’t respond normally to insulin, their ability to take up and store glucose, fatty acids and amino acids is impaired. This causes increases in blood sugar and lipid levels to abnormal levels and contributes to the development of the metabolic syndrome, a cluster of conditions which include abnormal elevations in triglycerides, blood pressure and fasting blood sugar, and abnormally low HDL (good) cholesterol. People with metabolic syndrome have a much greater chance of developing heart disease, stroke and diabetes.

Most importantly, this study highlights the role of sleep in maintaining normal body metabolism. These findings make clear why we see such serious health problems among people with poor sleep habits — workers whose shifts require abnormalities in sleep patterns and people with sleep disorders such as insomnia, teenagers who stay up late, but have to be at school early.

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Parents concerned about their child’s weight might want to look at their child’s sleep habits before tackling their eating habits. Explain the health and weight benefits to children and adolescents and try to arrive at an agreed-upon time for “lights out.” Kids are likely to feel better about getting more sleep if they understand it may help them avoid gaining weight.

Esther Entin, M.D. is a Board Certified pediatrician and Clinical Associate Professor of Family Medicine at Brown University’s Warren Alpert School of Medicine

The opinions expressed are solely those of the author and do not necessarily reflect the views of Comcast.