The recommended hours of sleep for adults to achieve healthy living is six to eight hours but scientist said sleeping more than those hours is linked with increased risk of cardiovascular (CVD) disease and premature death. According to the findings of a new study published in the ‘European Heart Journal’, compared with people who slept six to eight hours a night, those who slept eight to nine hours had a five per cent increased risk for CVD or death. Lead author of the study Chuangshi Wang who is a doctoral student at the McMaster University in Hamilton, Ontario, Canada, urged adults to get enough sleep — that is, six to eight hours a day.
“But if you sleep more than nine hours a day, you may want to visit a doctor to check your overall health,” he added.” People who slept nine to 10 hours had a 17 per cent increased risk, and those who slept more than 10 hours increased their risk by 41 per cent. The researchers also found a nine per cent increased risk in people who slept less than six hours, but that difference was not statistically significant. Daytime naps also increased the risk for cardiovascular events, but only in people who slept more than six hours a night. The researchers controlled for age, body mass index, physical activity, diabetes, depression, smoking, alcohol consumption and many other health and behavioral characteristics.
The researchers gathered health and lifestyle information, including self-reported sleep data, on 116,632 people in 21 countries, followed them up for over eight years and recorded 4,381 deaths and 4,365 major CVD events. CVD events refer to any incident that may cause damage to the heart muscle. The heart is a busy organ, constantly pumping blood filled with oxygen and nutrients through your arteries, into the heart muscle (myocardium). Any interruption of blood flow will lead to an injury, or infarction.