Lack of sufficient sleep may increase the risk of diabetes by reducing the body’s sensitivity to insulin and impairing its ability to regulate blood sugar, a new study has warned.
The study adds to a growing body of information linking lack of sleep to a range of ailments including obesity, metabolic syndrome, mood disorders, cognitive impairment and accidents.
“We found that when people get too little sleep it leaves them awake at a time when their body clock is telling them they should be asleep,” said lead author Kenneth Wright Jr, professor at University of Colorado Boulder in US.
“And when they eat something in the morning, it impairs their ability to regulate their blood sugar levels,” said Wright.
Wright and co-author Robert Eckel, professor at University of Colorado Anschutz Medical Campus, looked at 16 healthy men and women in their study.
Half of the test subjects initially slept for up to five hours a night for five days to simulate a regular work week.
Then they slept for up to nine hours a night for five days. The other half completed the sleep conditions in the opposite order.
Blood tests later showed that those who slept five hours a night had a reduced sensitivity to insulin, which in time could increase the risk of getting diabetes.
However, when they slept nine hours a night, oral insulin sensitivity returned to normal. Still, it was not enough time to restore intravenous insulin sensitivity to baseline levels.
“We did a study last year showing weight gain is caused by a lack of sleep and now we find that there could also be a risk of diabetes,” said Eckel.
“While the exact mechanisms are unknown, it’s clear that a lack of sleep causes metabolic stress,” he said.
“We have a clock in our brain which controls 24-hour patterns in our physiology and behaviour. It also controls the release of the hormone melatonin which signals our body that it’s night time,” Wright said.
High melatonin levels at night tell us to sleep. But if a person eats instead of sleeps during this time, it may alter the way the body responds to the food, impairing insulin sensitivity, he said.
“The body has to release more insulin to keep blood sugar levels normal,” Wright said.
“Our bodies can adapt initially but over the long term they may not be able to sustain it,” he said.
The study was published in the journal Current Biology.