Feeling excessively sleepy is also associated with metabolic syndrome

Taking long naps could trigger conditions linked to heart disease, according to a new study.

Napping for more than 40 minutes or feeling excessively tired during the day is associated with metabolic syndrome.

The term is used to describe a rise in blood pressure, cholesterol and blood sugar, as well as excess fat around the waist. Metabolic syndrome in turn raises the risk that a person will have heart disease.

As sleeping during the day is prevalent around the world, researchers hope that the findings will help to create new treatments for metabolic disease as rates of the conditions rise. 

The team at the University of Tokyo analysed data from 21 observational studies on 307,237 subjects. 

Scientists asked the participants questions about their napping habits, as well as whether they felt sleepy during the day. 

The results were compared to their history of metabolic syndrome, type-2 diabetes and obesity. 

The study builds on previous evidence that Dr Tomohide Yamada, lead author of the study, and his team used to link lengthy naps and daytime lethargy to heart disease and type-2 diabetes. 

The new research will be presented at the American College of Cardiology's 65th Annual Scientific Session.

“Sleep is an important component of our healthy lifestyle, as well as diet and exercise,” Yamada said.

Further research is now needed to determine how sleep habits influence metabolic syndrome and cardiovascular disease, as well as if short naps can be beneficial. 

The findings come after scientists at Loughborough University reported that women need more sleep because of their “complex” brains.

On average, women needed 20 minutes more sleep than men because the female brain is used more during the day, and needs to recover. 

Men with complex jobs involving “decision-making and lateral thinking” may also more sleep than the average male.