'Too much sleep' can be bad for the heart, study finds

Women most likely to be at risk from heart problems even if they sleep 'too much or too little'

Sleeping more than eight hours a night increases the risk of heart disease, a study has found.

According to the research, those who have eight hours or more sleep become 34 per cent more likely to suffer from the disease - while those who sleep for less than four hours are 35 per cent more likely to be at risk of cardiovascular problems.

Previous studies have shown a lack of sleep is linked to stress, increased blood pressure and the secretion of adrenaline, all of which are factors in the increased risk of heart disease.

However, the researchers behind the study at the Norwegian University of Science and Technology are unsure as to why more sleep appears linked to a higher risk of heart problems.

“We don’t know which mechanism can explain a direct causal link between long sleep duration and an increased risk of dying from coronary heart disease,” said lead author Dr Linn Beate Strand.

The study used information collected from 400,000 Taiwanese adults who had medical check-ups between 1994 and 2011.

Participants, aged 20 and older, were asked how long they slept for, from zero to more than eight hours a night.

The findings showed those who slept for between six and eight hours were most likely to die from cardiovascular problems.

Researchers found during a follow-up that 711 people died from cardiovascular disease.  

The results also showed women in both groups were more at risk of the disease than men.

Dr Strand said: “Women are more prone to sleep problems than men, and previous studies have also shown that women who sleep a little or a lot may be at increased risk for cardiovascular.

“Our results show that enough, but not too much sleep, is important for a healthy lifestyle.”

Study authors said adequate sleep duration should be considered an important component of a healthy lifestyle.