Bad sleep doubles danger of heart attacks
‘Stress of waking up at night’
THOSE who toss and turn in bed at night are twice as likely to have a heart attack, a major study suggests.
Scientists said fragmented sleep should be considered an early warning sign of future health problems.
a study of nearly 13,000 people found that those who woke up repeatedly in the night were 99 per cent more likely to suffer from ischaemic heart disease – the medical term for a heart attack or severe angina.
Those 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 had less than six hours of sleep a night were 24 per cent more likely to have a heart attack.
Experts are not sure if poor sleep actually causes heart problems, or whether those who are ill and already suffering symptoms are simply getting worse sleep.
But either way, they warn that having a restless night should be considered a red flag for more serious concerns.
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 looked only at statistical trends, rather than the reasons behind the link between sleep and heart problems.
But Dr Sasaki, who yesterday presented his findings at the European Society of Cardiology congress in Barcelona, suspects poor sleep disrupts the way the body runs its core functions – pulse, breathing and blood pressure. This combined system is called the ‘sympathetic nervous system’, which operates without us having to consciously think about it.
The system is run by a part of the brain called the adrenocortical axis, which is highly sensitive to hormone imbalances and fluctuations in stress. Dr Sasaki thinks poor sleep – particularly the stress of waking up at night – may have an impact on this sensitive part of the brain, which in turn could raise heart rate and blood pressure, increasing strain on the heart.
He concluded: ‘Our results support the hypothesis that sleep deterioration may lead to cardiovascular disease. 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 those 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.
Professor Metin avkiran, of the British Heart Foundation, said: ‘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.’