Higher quality upper-body muscles, particularly in the chest and back, are associated with a reduced risk of heart attack and death, according to a new study published in the journal Radiology. The findings emerged from an analysis of CT scans of 1,722 patients who underwent the scans for chest pain between 2010 and 2014.
Researchers from the University of Edinburgh utilized artificial intelligence to examine CT scans, focusing on a measure known as 'skeletal muscle attenuation.' This metric indicates the quality of muscle tissue, where lower readings suggest more fatty infiltration and thus lower muscle quality. The study tracked patients for a decade, during which 133 died and 106 experienced a heart attack.
The analysis revealed that individuals with higher skeletal muscle attenuation, indicating denser and healthier muscles, had a significantly lower risk of experiencing a heart attack or death. Specifically, for every 10-point increase in a measure of muscle brightness on the scans – which correlates with muscle density – participants were 31% less likely to have a heart attack and 39% less likely to die within the 10-year follow-up period. These associations held even after accounting for other risk factors like age, sex, and arterial calcium buildup.
Interestingly, the study found no link between overall muscle size and the risk of heart attack or death, emphasizing that muscle composition and quality are the critical factors. This suggests that being physically active, leading to better muscle quality, is more important than simply having large muscles.
The muscles examined in the scans, primarily part of the chest, back, and intercostal muscles between the ribs, are likely indicators of broader physical fitness. Professor Bryan Williams OBE, Chief Scientific and Medical Officer at the British Heart Foundation, suggested that individuals with denser muscle mass are likely more physically active, which contributes to better heart health. He highlighted that regular exercise can reduce cardiovascular disease risk by up to one-third.
The AI tool used in the research accelerated the muscle quality assessment process, reducing analysis time from hours to minutes. The study authors propose that routine heart scans could potentially be used in the future to predict heart attack risk, enabling earlier interventions and lifestyle modifications for high-risk individuals.
While the findings are promising, further research is needed to fully understand the relationship between exercise, muscle density, and heart health. The study also noted that fat deposits in the torso and liver were not significantly linked to heart attack risk in their analysis. These findings come as cardiovascular disease remains the leading cause of death in the UK, with obesity identified as a major contributing factor.