Research shows that extra sleep may cut females’ risk of diabetes.
However, the opposite is true for males, with men who stayed snuggled under the duvet thought to be at higher odds of developing the condition.
The discovery is important because diabetes rates are soaring as waistlines expand.
The condition leads to disabling and life-threatening complications from stroke and heart attacks, to blindness, kidney disease and circulatory problems that lead to limbs being amputated.
Learning more about what fuels diabetes could have huge health and economic benefits.
A Dutch-led team of researchers studied almost 800 healthy middle-aged men and women.
The volunteers wore a device that tracked their sleep and underwent tests to show how well their body was able to use insulin, the sugar-processing hormone at the root of diabetes.
In type 2 diabetes, the body does not make enough insulin – or struggles to use the insulin that is made.
The volunteers slept for an average of seven hours and 18 minutes.
When the women slept longer than this, their bodies were better at using insulin.
And the longer they slept, the more responsive they were to the hormone, suggesting their risk of diabetes was reduced.
Interestingly, lack of sleep was also linked to better use of insulin in women.
However, the results were very different for the men studied.
There, sleeping more than average cut their ability to use insulin, meaning they may be at greater risk of diabetes.
Short sleep was also detrimental to males, the Journal of Clinical Endocrinology & Metabolism reports.
Researcher Dr Femke Rutters, of the VU Medical Centre in Amsterdam, said: ‘In a group of nearly 800 healthy people, we observed sex-specific relationships between sleep duration and glucose metabolism.
‘In men, sleeping too much or too little was related to less responsiveness of the cells in the body to insulin, reducing glucose uptake and thus increasing the risk of developing diabetes in the future.
‘In women, no such association was observed.
‘This research shows how important sleep is to a key aspect of health.’
Men are known to get less deep, restorative sleep than women, and so their health may suffer more from sleep deprivation.
It is less clear why extra sleep is bad for men but good for women.
However, it is possible that men who regularly oversleep are already ill in some way.
Previous research has shown that while women spend longer in bed than men, they get less sleep.
The Cambridge University researchers said that the problems of juggling work and family life may leave females tossing and turning.
The study was published in the Journal of Clinical Endocrinology & Metabolism.