Getting anywhere between six to nine hours sleep is ideal for your heart, but any more or less could potentially boost your risk of cardiovascular afflictions, including coronary heart disease or a stroke. At least, that’s according to a new study – led by the Onassis cardiac surgery center in Athens – presented at the European Society of Cardiology Congress in Munich this week.
Around 17.7 million people die each year from cardiovascular diseases, primarily heart attacks and strokes – that’s 31 percent of all deaths, by the way. Smoking, unhealthy diets, physical inactivity, and a high salt intake are all linked to increased likelihood of these problems. A lack of sleep has been thought to be a factor too, although it’s been uncertain how big a factor it might be.
This new study sounds like an easy fix then: get more sleep on a regular basis and lower your risk. There are, as ever, some caveats – not least that the study isn’t available to read yet.
So what's the story? Well, the good news is that it's a meta-analysis, a study that reviews data from many pre-existing studies in an attempt to find correlations or trends. In this case, the data involved a million adults spread across 11 studies.
According to the abstract, it appears that those that got fewer than six hours per night had an 11 percent increased risk of getting a heart condition over the following nine years, compared to those that got those requisite hours of sleep. Those that slept for more than nine hours had a 32 percent increased risk over the next nine years.
No cause-and-effect relationship between sleep and heart health is given here. Sleep is known to have an influence on metabolism, blood pressure, and inflammation, but specific links between sleep and heart health are somewhat elusive.
More importantly, however, this talks about relative risk. Absolute risk is your current, actual risk: for example, let’s say you have a 10 percent risk of sneezing today. That means today, you’ll have a one-in-ten chance of sneezing.