Napping for more than an hour in the daytime may raise the risk of Type 2 diabetes by 45 per cent a new study shows. Researchers at the University of Tokyo used data from 21 studies involving more than 300,000 people who had recorded their daily level of napping.
They found that after 60 minutes napping appears to become harmful with the risk increasing the more time a person is asleep. However there was no risk before one hour.
The scientists believe that failing to complete a sleep cycle could be behind the increased risk.
According to the researchers, long naps could be a result of disturbed sleep at night, potentially caused by sleep apnoea. This could even increase the risk of heart attacks, stroke, cardiovascular problems and other metabolic disorders, including type-2 diabetes.
The risk of type-2 diabetes can even increase due to sleep deprivation, caused by work or social life patterns. But it was also possible that people who were less healthy or in the early stages of diabetes were more likely to nap for longer during the day. Shorter naps, in contrast, were more likely to increase alertness and motor skills, the authors said.
Naveed Sattar, professor of
metabolic medicine at the University of Glasgow, said “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.” However, he even mentioned that proper trials were needed to determine whether sleeping patterns made a difference to “real health outcomes”.Dr Benjamin Cairns, from the cancer epidemiology unit at the University of Oxford, said the findings should be treated with caution, “In general, it is not possible to make conclusions about cause and effect based on observational studies alone, because usually they cannot rule out alternative explanations for their findings.”
The study is being presented at a meeting of the European Association for the Study of Diabetes in Munich.
