Men who don’t have enough sleep during the working week and catch up at the weekend could be reducing their risk of developing type 2 diabetes. This was the message from a US study presented at a scientific meeting this week.
Peter Liu, a lead researcher at Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (LA BioMed), and colleagues, tested men whose lifestyles meant they had chronic sleep restriction during the working week.
They found the men’s insulin sensitivity, or ability to clear blood sugar or glucose from their bloodstream, significantly improved after three nights of “catch-up” sleep at the weekend.
The findings were presented at The Endocrine Society’s 95th Annual Meeting, which ran from 15-18 June in San Francisco.
Liu says in a statement:
“We all know we need to get adequate sleep, but that is often impossible because of work demands and busy lifestyles.”
“Our study found extending the hours of sleep can improve the body’s use of insulin, thereby reducing the risk of Type 2 diabetes in adult men,” he adds.
Type 2 diabetes affects nearly 26 million Americans and costs the nation an estimated $174 billion. It is the seventh leading cause of death in the US.
It develops when the body either doesn’t produce enough insulin (the hormone that helps keep blood sugar or glucose under control), or it cannot use the insulin it produces.
Retaining the body’s sensitivity to insulin reduces the risk of developing type 2 diabetes.
Experiments that restrict sleep in healthy people show this can harm insulin sensitivity.
Although we don’t know exactly what causes the disease, a US study published in JAMA in April 2013, suggests the risk of developing type 2 diabetes may be linked to melatonin secretion during sleep.
Liu and colleagues set out to discover what happens to insulin sensitivity in people who habitually lose sleep during the week (for instance because of their job or busy lifestyle), and catch up at the weekend.
Their findings suggest this may well be the case, as Liu explains:
“The good news is that by extending the hours they sleep, adult men – who over a long period of time do not get enough sleep during the working week – can still improve their insulin sensitivity.”
For the study, Liu teamed up with researchers from the University of Sydney in Australia. They recruited 19 non-diabetic men of average age 29, who reported they had not been getting enough sleep during the working week for a number of years (the average being around 6.2 hours of nightly sleep during the working week over an average of 5.1 years).
However, the men said they regularly made up for lost sleep at the weekend, during which on average, they slept for an extra 2.3 hours per night (an extra 37.4%).
To confirm the men’s reported sleep times, the researchers asked them to wear actigraph devices on their wrists that monitored when they were asleep and when they were awake.
The researchers then invited the men to spend three nights, over two separate weekends, in a sleep lab.
Each participant was randomly assigned two of three sleep patterns (one weekend for one pattern, the other weekend for the other).
In one pattern, the men slept for 10 hours without disturbances, in another they slept for six hours, and in the third pattern they slept for 10 hours but were disturbed by noises (not enough to wake them but enough to arouse them into shallow sleep).
On the fourth day, first thing in the morning, the men gave fasting blood samples so the researchers could test their insulin sensitivity.
All the men ate the same food during their stay in the sleep lab, so that food intake could be ruled out as an influencing factor, says Liu.
When they analyzed the results, the team found insulin sensitivity was much improved when the men slept 10 hours a night at the weekend compared to when they had persistent sleep restriction (ie were only allowed to sleep 6 hours a night).
Funds from the US National Institutes of Health’s National Center for Advancing Translational Sciences and from Australia’s National Health and Medical Research Council helped finance the study.
Written by Catharine Paddock PhD