A study of teenagers in the US found that the less sleep they got, the higher the chance of them having insulin resistance, a metabolic condition that increases a person’s risk of developing type 2 diabetes.
The researchers, writing in the October issue of the journal Sleep, suggest increasing the amount of sleep teenagers get could protect them against diabetes in the future by improving their insulin resistance.
Insulin is a hormone made in the pancreas that helps the body use glucose, its main source of energy. Insulin resistance is where the body is producing the hormone, but can’t use it properly: the muscle, fat and liver cells don’t respond to insulin as well as they should. This puts a greater demand on the pancreas to make more insulin.
Without treatment, the demand for insulin becomes bigger than the pancreas can cope with, sugar builds up in the blood, and the stage is set for developing full blown type 2 diabetes. Insulin resistance also raises the risk for heart disease.
Karen Matthews, of the Department of Psychiatry at the University of Pittsburgh in the US, is lead author of the new study. She told the press:
“We found that if teens that normally get six hours of sleep per night get one extra hour of sleep, they would improve insulin resistance by 9 percent.”
Matthews says their study is the first to show a relationship between shorter sleep and insulin resistance that is independent of obesity in healthy adolescents.
For their study, the authors measured sleep duration and insulin resistance in 245 healthy high school students over a week during the school year.
During the week of observation, participants provided a fasting blood sample, wore a wrist actigraph (to measure duration of inactive periods) and kept a sleep log.
According to actigraph readings, the participants averaged 6.4 hours of sleep over the week, with school days significantly lower than weekends.
The results showed that higher insulin resistance was tied to shorter sleep duration. This was found to be independent of potential influencing factors such as age, gender, race, waist size, and body mass index.
There was no evidence that long sleep was linked to insulin resistance.
Matthews and colleagues suggest interventions to extend sleep duration may reduce diabetes risk in youth.
The American Academy of Sleep Medicine says most teenagers need just over nine hours of sleep a night.
Written by Catharine Paddock PhD