How much sleep a night cuts diabetes risk?

The lowest risk was seen in women who slept for seven to eight hours a night throughout their life. Photo / iStock

With work piling up in the office, it's easy to fall into a pattern of staying "just an hour or two later".

But before you know it the hours have sped by, and when you finally leave it's almost time for bed. By the time your head hits the pillow it won't be long before your alarm goes off - and the cycle begins again.

But working women burning the candle at both ends should beware, say scientists, because sleeping less than six hours a night increases their risk of developing type 2 diabetes. And the damage done by sleep deprivation at the height of your career can't be undone by enjoying lie-ins in retirement.

For those who increase their sleep duration in later life have a 15 per cent higher chance of developing the illness, found a Harvard study of 59,031 women aged 55 to 83.

Notably women who increased their sleep were more likely to have been short sleepers to begin with.

The lowest risk was seen in women who slept for seven to eight hours a night throughout their life. Researchers found this was the optimum amount of sleep to maintain, with even those who slept for seven hours at the start of the 14-year study seeing their risk increase if they upped their sleep duration.

It is suspected that the link between sleep and diabetes is down to substances that circulate in our blood while we sleep, changing the way the body's metabolism functions.

Pro-inflammatory cytokines - substances linked to the sleep-wake cycle - also have an impact on the way glucose is processed, a key factor of type 2 diabetes. Writing in the journal Diabetologia, the team from the Harvard T.H. Chan School of Public Health said: "Chronic short sleep duration and increases in sleep duration are associated with increased risk of diabetes.

"Shortened sleep is related to glucose intolerance, insulin resistance and reduced acute insulin response to glucose... while increases in sleep duration have modest, adverse associations with weight gain."

They added: "The mechanisms underlying the sleep-diabetes relationship remain unsettled, as does the degree of mediation by lifestyle."

- Daily Mail