The research by Japan experts looked at data from 21 studies concerning more than 300,000 people and found the association between daytime snoozes and type 2 diabetes. Following the examination of potential factors, it was discovered that taking a long nap of more than 60 minutes during the day drastically increased the risk of type 2 diabetes, but when less than a few minutes has no effect.
Japan experts said that: ‘Longer nap was associated with increased risk of diabetes and metabolic syndrome. Further studies are needed to confirm the efficacy of a short nap. Some people cannot get enough sleep at night due to social life and work life related factors.
‘Taking naps is widely prevalent around the world.
‘Daytime naps are usually brief, but can range from a few minutes to a few hours.
‘The frequency varies from taking an occasional nap to planned rest periods even several times daily for habitual nappers.
‘Some individuals take a nap because they are excessively sleepy during the daytime as a result of a sleep disorder.’
Professor Naveed Sattar, from the University of Glasgow, said: ‘This observational study shows an association between longer naps and diabetes.
‘It’s likely that risk factors which lead to diabetes also cause napping.
‘This could include slightly high sugar levels meaning napping may be an early warning sign of diabetes.
‘That said, there is now abundant evidence of a link of sorts between sleep disturbances and diabetes. What we need are trials to determine if, when and for how long one sleeps makes a difference to real health outcomes.
‘Trials bring truth and without proper trials, we simply will never know the answer.’