Strong torso muscles linked to lower heart attack risk

People with strong muscles in their chest and back are less likely to have heart attacks, according to a new study led by Professor Michelle Williams from the Institute for Neuroscience and Cardiovascular Research.

Using artificial intelligence, the Williams lab analysed routine heart scans from more than 1700 people who had chest pain. People with greater muscle density in their chest and back were less likely to have a heart attack or die in the decade after having the scan.

The research team think that people with this type of good-quality skeletal muscle are those who exercise more and have greater strength in their torsos. 

The results suggest this could help to reduce the risk of having a heart attack or dying early, experts say. 

Measuring muscle density

Around 350,000 people have a CCTA scan in the UK each year to identify any narrowing or blockages in the coronary arteries that supply the heart muscle with blood, which may put them at risk of a heart attack. 

The University of Edinburgh-led research team took a deeper dive into CCTA scan images, using AI to examine people’s muscle, organs, bones and the fat within their upper bodies. This included looking at skeletal muscle attenuation – the brightness or darkness of the muscle in a scan. 

A brighter image indicates that someone has better quality, more dense muscle, which may contain a lower proportion of fat. Fat within people’s muscle has previously been linked to poor cardiovascular health. 

The new study grouped people based on how their muscle appeared in scan images, and investigated rates of heart attacks and early deaths using health records. 

Reduced risk of heart attack and death

For every 10-point increase in scan brightness, indicating better quality muscle with less fat, a person was calculated to be 31 per cent less likely to have a heart attack. They were also 39 per cent less likely to die in the 10 years after having the scan. 

This was seen even after taking into account other factors which may increase people’s risk of heart attacks and death, including their age, sex and the amount of calcium which had built up in their arteries. 

The AI used in the study took no longer than a minute to measure the quality of someone’s muscle from a single scan. A radiologist would take several hours to do the same thing.

woman lifting wights overhead at the gym flaxing back muscles

Heart protection

More evidence is needed on how people’s muscle quality may affect their heart health or risk of dying prematurely, researchers say. It is likely that people who exercise enough to have strong muscles in their upper body have a healthy lifestyle which protects their heart in other ways, they add.  

All kinds of exercise, not just strength-training, can improve muscle density. The size of people’s muscles was not linked to their risk of a heart attack or early death, suggesting it is the composition of the muscle which matters.

The results suggest that routine heart scans could in future be used to identify people with less good-quality muscle who may be at greater risk of heart attacks, experts say. Higher risk people could then be helped to exercise more, be monitored more closely, or prioritised for drugs such as statins, which can reduce the risk of a heart attack, they add. 

However, more research is needed before scans could be relied upon in this way. 

The study, part-funded by the British Heart Foundation, was published in the journal Radiology.

It is fascinating that people’s skeletal muscle could be linked to their risk of having a heart attack. The muscles which show up in the scans we used – coronary computed tomography angiogram scans – are principally the back muscles, part of the pectoral muscles (or ‘pecs’) and the intercostal muscles between the ribs. 

“So I am now personally interested in exercises like cycling, planks and pilates, which I enjoy and may have an effect on these muscles. However we need far more research to better understand how exercise may affect muscle density, and how this may relate to heart health.

Professor Michelle Williams Personal Chair of Cardiovascular Imaging, Institute for Neuroscience and Cardiovascular Research

Artificial intelligence can rapidly reveal information buried in scan results which provides a more detailed picture of our health than ever before.  

“It is likely that people in this study with more dense muscle mass were more physically active and as a result may have better heart health. That is yet more evidence supporting the power of exercise. 

“Every time we move, we are making a positive difference to our muscles, our blood vessels and our overall health, and regular exercise can reduce the risk of cardiovascular disease by up to a third.

Professor Bryan Williams OBE Chief Scientific and Medical Officer at the British Heart Foundation

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