People with denser backs and chests also have a lower risk of dying prematurely
Research from the University of Edinburgh has revealed a striking connection between muscle quality and cardiovascular health.
Scientists employed artificial intelligence to scrutinise hospital scans, discovering that individuals with denser chest and back muscles face significantly reduced risks of cardiac events.
The study, published today in the journal Radiology, found that those with higher-quality torso musculature were 31 per cent less likely to suffer a heart attack.
Perhaps more remarkably, these same individuals demonstrated a 39 per cent lower chance of dying prematurely over a ten-year period.
Researchers believe the findings point to exercise habits as the underlying factor.
The Edinburgh-led team analysed coronary computed tomography angiogram scans from 1,722 patients, predominantly aged in their fifties, who had presented with chest pain.
Artificial intelligence technology examined multiple aspects of participants' upper bodies, including muscle tissue, organs, bones and fat deposits.
A key measurement involved skeletal muscle attenuation — essentially how light or dark the muscle appears on imaging.
Denser muscle reflects more X-ray beams, producing a brighter image on scans. This brightness indicates superior muscle quality with lower fat content.
Crucially, the research determined that muscle size bore no relationship to heart attack risk or premature death. The composition of muscle tissue proved far more significant than its dimensions.
Prof Michelle Williams, the study's senior author, was so struck by the results that she has altered her own lifestyle.
"It is fascinating that people's skeletal muscle could be linked to their risk of having a heart attack," she said.
"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."
She now attends the gym twice weekly and aims for an hour's daily walking.
"So I am now personally interested in exercises like cycling, planks and pilates, which I enjoy and may have an effect on these muscles," Prof Williams added.
She acknowledged, however, that considerably more research is needed to understand precisely how physical activity influences muscle density and its relationship to cardiac wellbeing.
Prof Bryan Williams, chief scientific and medical officer at the British Heart Foundation, which part-funded the research, offered his assessment: "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."
Looking ahead, routine cardiac scans could potentially identify patients with poorer muscle quality who face elevated heart attack risks.
Such individuals might then receive targeted support for increased physical activity, closer monitoring, or priority access to preventative medications.