Tossing and turning at night could double the risk of a heart attack
People who toss and turn in their sleep are twice as likely to suffer a heart attack, research suggests.
Scientists said regular waking in the night should be seen as a warning of future ill-health.
The study of nearly 13,000 people found that people who struggled to sleep through the night were 99 per cent more likely to suffer from heart attacks or severe angina.
Those who took more than half an hour to fall asleep or got less than six hours of sleep a night were also at increased risk.
The Japanese research did not establish why there were such a strong association between sleep and heart health.
But scientists said that the act of constant waking might cause “overactivity” in the nervous system, which could raise heart the heart rate and blood pressure, placing extra strain on the heart.
Poor sleep could also be a symptom of poor health, meaning that those with heart problems were less likely to get a decent night’s sleep.
The research found people who took more than half an hour to fall asleep had a 52 per cent increased heart attack risk and 48 per cent increased risk of a stroke.
And those who got less than six hours of sleep a night were 24 per cent more likely to have a heart attack.
Study leader Dr Nobuo Sasaki, of Hiroshima University in Japan, said: “Poor sleep in patients with ischaemic heart disease may be characterised by shorter sleep and brief moments of waking up.”
His study examined statistical trends, so could not establish the reasons for the links.
But Dr Sasaki, presenting his findings at the European Society of Cardiology congress in Barcelona, said that poor sleep could disrupt the way the body runs its core functions — pulse, breathing and blood pressure.
The act of waking was likely to disturb the body’s sympathetic nervous system, he said.
The main function of the system is to activate the physiological changes that occur during the body’s fight-or-flight response.
This could result in raised heart rate and blood pressure, increasing strain on the heart.
Dr Sasaki concluded: “Our results support the hypothesis that sleep deterioration may lead to cardiovascular disease. Poor sleep in patients with ischaemic heart dis- ease may be characterised by shorter sleep and brief moments of waking up.”
He added: “Difficulty maintaining sleep reflects an increase in sleep fragmentation, which refers to brief moments of waking up and causes overactivity of the sympathetic nervous system and adrenocortical axis.”
Previous research, published by the University of California San Francisco last year, suggests people who do not sleep all the way through the night are at a 29 per cent increased risk of developing an irregular heartbeat.
Sleep problems have also been linked to increased risk of cancer, obesity, diabetes and Parkinson’s.
A study published in 2014 suggested people in the UK get two hours less sleep a night than they did 60 years ago.
Professor Metin Avkiran, Associate Medical Director at the British Heart Foundation, said: “Disturbed or poor-quality sleep can lead to increased heart rate, blood pressure and the release of chemicals linked
to inflammation of the heart — all of which put it under strain. Although the odd restless night is not harmful to our health, it could be a sign of something more serious if this becomes the norm.”
“Making some small lifestyle changes, such as eating a healthy balanced diet, reducing alcohol intake, and managing your stress levels, will all help to give you the best chance of a good night’s rest.”
Those with disrupted sleep were twice as likely to have heart attacks and angina.