According to a new study, both those who sleep less than four hours at night, and those who sleep more than eight hours, are at increased risk of dying from heart disease.
Norwegian and Taiwanese researchers are behind the study which reveals that both too much and too little sleep may increase the risk of heart attack and angina pectoris, forskning.no writes.
– This is the largest single study that has looked at how sleep duration affects the risk of dying from cardiovascular disease. Our results reveals that enough, but not too much sleep is an important part of a healthy lifestyle, researcher Linn Beate Strand at the Department of Community Medicine at NTNU says.
She says that scientists are still not certain on how sleep affects the risk of dying from cardiovascular disease, but there are several theories.
– Poor sleep is associated for example with stress responses that increase heart rate, blood pressure and secretion of adrenaline, which all are known risk factors for cardiovascular disease, says Strand.
The researchers do not know the mechanisms that may explain a direct causal link between long sleep duration and increased cardiovascular risk.
According to the study it is mainly women who are at increased risk due to too short and too long sleep duration. The correlation between sleep duration and the risk of dying from cardiovascular disease was also slightly stronger for the persons older than 65 years than those who were younger.
Source: NTB scanpix / Norway Today