How many hours do you get? The perfect amount of sleep to lower heart attack risk

Sep 03, 2019
Sleeping too little is just as bad as sleeping too much when it comes to the risk of heart attacks. Source: Getty

While most people know that smoking, an unhealthy diet and being inactive can dramatically increase the risk of suffering a heart attack, alarming new research shows healthy people could also be at risk if they don’t get the right amount of sleep each night. Researchers from the University of Colorado believe that non-smokers who exercise and have no genetic predisposition to cardiovascular disease increase their chance of a heart attack when they skimp on sleep or get too much of it.

The research, published in the Journal of the American College of Cardiology, analysed 461,000 people and also found that people who have a high genetic risk for heart attack can actually offset the risk of they sleep between six and nine hours a night. Researchers say that the findings prove that sleep duration is a key factor when it comes to overall heart health.

For the study, experts analysed the genetic information, sleeping habits and medical records of participants aged between 40 and 69 who had never had a heart attack. Each participant was followed for seven years to determine whether sleep impacted the risk of an attack.

It was found that people who slept less than six hours each night were 20 per cent more likely to have a heart attack during the study period when compared to those who slept between six and nine hours. Sleeping longer also increased the risk, with those sleeping more than nine hours 34 per cent more likely to experience a heart attack.

In participants with a genetic predisposition to heart disease, sleeping between six and nine hours a night cut their risk of suffering a heart attack by 18 per cent. The study’s lead author Iyas Daghlas explained: “It’s kind of a hopeful message, that regardless of what your inherited risk for heart attack is, sleeping a healthy amount may cut that risk just like eating a healthy diet, not smoking, and other lifestyle approaches can.”

Previous studies have shown an association between sleep and heart health but because most of those are observational studies, it’s been difficult for researchers to determine whether poor sleep causes heart problems or if heart issues impact sleep. Given that many factors can influence both heart health and sleep, it’s even more difficult for experts to determine cause and effect.

The new study combined observational and genetic research and considered other potential factors such as body composition, physical activity, socioeconomic status and mental health. Researchers found that sleep duration still influenced heart attack risk independently of these other factors.

Those whose sleep duration fell most outside the six to nine hour sleep range had an even greater risk of a heart attack. For example, a person who slept just five hours a night had a 52 per cent greater risk of a heart attack compared to someone who slept between seven and eight hours. Those who sleep for 10 years were twice as likely to experience an attack.

Researchers also identified 27 genetic variants that are associated with short sleep and found that genetically influenced short sleep duration was also a risk factor for heart attack. The study’s senior author Celine Vetter said: “This gives us even more confidence that there is a causal relationship here – that it is sleep duration, not something else, influencing heart health.”

Previous research has found that sleeping too little can impact the lining of the arteries and increase the risk of heart disease, while sleeping too much can increase inflammation – which is another factor associated with cardiovascular disease. According to the Heart Foundation Australia, age, gender, ethnic background and family history are risk factors people can’t change, but quitting smoking, managing cholesterol, reducing blood pressure, controlling diabetes, staying active, maintaining a healthy weight and eating a balanced diet can reduce the risk.

Meanwhile, another study released this year by researchers from the University of Colorado Boulder found people who don’t get enough sleep at night are at greater risk of suffering a heart attack or stroke – with people who sleep less than seven hours the most at risk.

People are advised to get between seven and nine hours of sleep a night, but around 40 per cent of all people fall short of this target. The sleep duration for the average American has fallen from nine hours per night to 6.8 hours in the last century and researchers in that study believed that seven or eight hours a night was important for genes that play a key role in vascular health.

It’s important to talk to a health professional about your individual risk factors so they can offer personalised advice on how you can reduce the risk.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.

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