Study: Less than six hours of sleep increases risk of heart disease, stroke

People with risk factors for heart disease and diabetes have greater chances of dying from heart-related diseases or stroke if they sleep less than six hours a night.

According to a study published in the Journal of the American Heart Association, the risk could be double that of people without the same risk factors, which is known as metabolic syndrome.

Previous studies had linked sleep deprivation to health conditions like high blood pressure, stroke and heart disease.

But the researchers, from the Hershey Medical Centre, Pennsylvania, say their study is unique because it’s the first to measure sleep duration in the laboratory rather than rely on self-reporting by patients.

The study used data from 1,344 men and women with an average age of 49. All the participants spent a night in a sleep laboratory.

Participants were assessed for metabolic syndrome with risk factors like being obese with a body mass index (BMI) of more than 30, high cholesterol, high blood pressure and elevated levels of fasting blood sugar and blood fats known as triglycerides.

Results showed that 39.2% of participants had at least 3 of the factors that increased their risk of heart disease.

Participants were monitored for an average of 16.6 years, during which period 22% of them died.

According to the results, participants who had metabolic syndrome and slept for more than 6 hours in the laboratory had a 49% higher risk of dying from heart disease or a stroke than those who did not have the risk factors.

However, those with metabolic syndrome and slept for less than 6 hours were slightly more than twice as likely to die of heart disease and stroke.

Also, those who slept least were more likely to die for any reason compared to those without metabolic syndrome.

Researchers say their results were credible because they considered other factors like sleep apnoea – a condition in which breathing stops during sleep and which is known to increase the risk of developing heart disease.

They say that future research should concentrate on whether longer sleep patterns could help people with metabolic syndrome.