Sleep six hours or risk heart disease and stroke
SLEEPING for fewer than six hours a night may increase the risk of suffering a heart attack or stroke, a study warns.
The findings suggest that poorquality sleep increases the risk of atherosclerosis – a build-up of plaque in the arteries.
Senior study author Professor Jose Ordovas, of the Centro Nacional de Investigaciones Cardiovasculares Carlos III in Spain, said: “This is the first study to show that sleep is independently associated with atherosclerosis throughout the body, not just in the heart.”
He said previous studies have shown that lack of sleep raises the risk of cardiovascular disease, by increasing heart disease risk factors such as glucose levels, blood pressure, inflammation and obesity.
The study was published in the Journal of the American College of Cardiology (JACC).
Researchers, led by JACC editorin-chief Dr Valentin Fuster, studied more than 3,900 bank employees with an average age of 46 in Spain.
All the participants had no known heart disease and two-thirds were men. They wore an actigraph – a device that continuously measures activity or movement – for seven days to measure their sleep.
Participants were divided into four groups: those who slept for fewer than six hours, for six to seven hours, for seven to eight hours and for more than eight hours.
The study found that, when traditional risk factors for heart disease were considered, participants who slept for fewer than six hours were 27 per cent more likely to have atherosclerosis throughout their body compared with those who slept for seven to eight hours.
And those who had a poor quality of sleep were 34 per cent more likely to have atherosclerosis compared with those who had a good quality of sleep.
Quality of sleep was defined by how often a person woke during the night and the frequency of movements, which reflect the sleep phases.
Dr Fuster added: “It is important to realise that shorter sleep duration that is of good quality can overcome the detrimental effects of the shorter length.”
The study also suggested that sleeping more than eight hours a night may be associated with an increase in atherosclerosis.