Using artificial intelligence (AI) to analyse routine heart scans of more than 1,700 adults—most of them in their 50s—who underwent imaging for chest pain, researchers found that individuals with denser skeletal muscles in their chest and back had a substantially lower risk of experiencing a heart attack or dying over the following decade.

The findings suggest that better muscle quality, rather than muscle size, could serve as an important indicator of long-term heart health, read the University of Edinburgh website.

AI reveals hidden heart health clues

Around 350,000 people in the UK undergo Coronary Computed Tomography Angiography (CCTA) scans every year to detect narrowing or blockages in the coronary arteries that supply blood to the heart.

In the new study, the University of Edinburgh research team used AI to examine routine CCTA scans in greater detail, assessing not only the heart but also skeletal muscles, bones, organs and fat distribution in the upper body.

The researchers specifically measured skeletal muscle attenuation—the brightness of muscle tissue on CT scans. Brighter muscle indicates denser, healthier muscle with a lower proportion of fat, whereas darker muscle suggests greater fat infiltration, which has previously been linked to poorer cardiovascular health.

Better muscle quality linked to lower risk

The study grouped participants according to muscle quality and tracked their health outcomes using medical records.

Researchers found that for every 10-point increase in muscle brightness on the scan—indicating better muscle quality and less fat infiltration—the risk of suffering a heart attack fell by 31 percent. The risk of dying within 10 years of the scan was also reduced by 39 percent.

These associations remained significant even after accounting for other major risk factors, including age, sex and the amount of calcium buildup in the coronary arteries.

AI completes analysis in under a minute

The AI system analysed muscle quality from a single heart scan in less than a minute, a task that would otherwise take a radiologist several hours to complete manually.

Researchers believe the technology could eventually become a valuable tool for identifying patients at elevated cardiovascular risk using scans they already undergo for other reasons.

Muscle quality matters more than muscle size

The researchers noted that muscle composition—not muscle size—was associated with heart health.

They suggest that people with denser muscles are often more physically active and may follow healthier lifestyles, factors that likely contribute to better cardiovascular outcomes. Importantly, all forms of physical activity—not just strength training—can improve muscle density.

While the findings are promising, researchers caution that more studies are needed to understand exactly how muscle quality influences heart health and whether improving muscle density directly reduces cardiovascular risk.

The results also raise the possibility that routine heart scans could one day help identify people with poorer muscle quality who may benefit from lifestyle interventions, closer monitoring or preventive treatments such as statins.

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