A new study has found that suboptimal sleep was associated with a higher likelihood of stroke and heart disease.
Nine in ten people do not get a good night’s sleep, according to research presented at European Society of Cardiology (ESC) Congress 2022, putting them at risk of stroke and heart disease.
The authors of the study estimated that seven in ten of these cardiovascular conditions could be prevented if everyone was a good sleeper.
“The low prevalence of good sleepers was expected given our busy, 24/7 lives,” study author, Dr Aboubakari Nambiema of the French National Institute of Health and Medical Research, explained.
“The importance of sleep quality and quantity for heart health should be taught early in life when healthy behaviours become established. Minimising night-time noise and stress at work can both help improve sleep.”
Previous studies on sleep and heart disease have focused on one sleep habit, such as sleep duration or sleep apnoea, where breathing stops and starts while sleeping. Other prior studies have often assessed sleep at baseline only.
The recent report, however, was based on a healthy sleep score combining five sleep habits.
The researchers investigated the association between the baseline sleep score, and changes over time in the sleep score, and incident cardiovascular disease.
The study included 7,200 participants, men and women aged 50 to 75 years, free of cardiovascular disease who were recruited in a preventive medical centre between 2008 and 2011. The average age was 59.7 years and 62 per cent were men.
Participants underwent a physical examination and completed questionnaires on lifestyle, personal and family medical history, and medical conditions.
The questionnaires were used to collect information on five sleep habits at baseline and two follow-up visits. Each factor was given one point if optimal and zero if not. A healthy sleep score ranging from zero to five was calculated, with zero or one considered poor and five considered optimal.
Those with an optimal score reported sleeping seven to eight hours per night, never or rarely having insomnia, no frequent excessive daytime sleepiness, no sleep apnoea, and an early chronotype – being a morning person.
The researchers checked for incident coronary heart disease and stroke every two years for a total of 10 years.
At baseline, 10 per cent of participants had an optimal sleep score and eight per cent had a poor score. During a median follow-up of eight years, 274 participants developed coronary heart disease or stroke.
The researchers analysed the association between sleep scores and cardiovascular events after adjusting for age, sex, alcohol consumption, occupation, smoking, body mass index, physical activity, cholesterol level, diabetes, and family history of heart attack, stroke or sudden cardiac death.
They found that the risk of coronary heart disease and stroke decreased by 22 per cent for every one point rise in the sleep score at baseline.
More specifically, compared to those with a score of zero or one, participants with a score of five had a 75 per cent lower risk of stroke or heart disease.
The scientists also estimated the proportion of cardiovascular events that could be prevented with healthier sleep and found that if all participants had an optimal sleep score, 72 per cent of new cases of coronary heart disease and stroke might be avoided each year.
Over two follow-ups, almost half of participants (48 per cent) changed their sleep score. While in 25 per cent it decreased, in 23 per cent it improved.
When the researchers examined the association between the change in score and cardiovascular events, they found that a one point increment over time was associated with a seven per cent reduction in the risk of coronary heart disease or stroke.
“Our study illustrates the potential for sleeping well to preserve heart health and suggests that improving sleep is linked with lower risks of coronary heart disease and stroke,” Dr Nambiema added.
“We found that the vast majority of people have sleep difficulties. But given that cardiovascular disease is the top cause of death worldwide, greater awareness is needed on the importance of good sleep for maintaining a healthy heart.”
