Key take-aways
New research finds that low fitness levels and older age are strong and independent risk factors for heartbeat irregularities, or arrhythmias*, in healthy adults. These arrhythmias were previously thought to be harmless, but are now considered to be an indicator of future cardiovascular risk (1,2)
The results support the introduction of age-based arrhythmia screening in over 50s, to allow for early intervention before symptoms arise to alter the trajectory of disease
There was a particularly strong association between lower aerobic fitness and risk of frequent and complex atrial arrythmias, highlighting the critical role of physical fitness in preserving the electrical stability of the heart
Madrid, Spain - 27 August 2025: New research has revealed that older age and low aerobic fitness levels are strong and independent risk factors for a high burden of heartbeat irregularities, known as arrhythmias*, that indicate future cardiovascular risk. The research was conducted in healthy participants between the ages of 40 and 60 years old with no heart symptoms.
The findings are being presented today at the 2025 European Society of Cardiology Congress in Madrid, Spain.
The researchers found that specific heart abnormalities, known as atrial arrhythmias, were closely associated with older age and fitness levels. Participants with lower fitness levels in particular had significantly higher risk of frequent and complex atrial arrhythmias. Old age was also a risk factor for ventricular arrhythmias.
The results support age-based arrhythmia screening after the age of 50 to prevent heart disease, and highlights the important protective role of fitness in reducing arrhythmia risk - even for healthy individuals who do not yet have any heart symptoms.
The study was led by Dr Amit Moses, from the Chaim Sheba Medical Center, Israel. He explained, "These findings are a powerful reminder that the heart often whispers before it shouts. Subtle signs, such as frequent irregular heartbeats and complex arrhythmias, give us an early warning of future risk before symptoms occur. This could allow early intervention to alter the trajectory of disease, allowing us to move to a new era of anticipatory heart medicine."
"We were particularly struck by the strength of the association between lower aerobic fitness levels and higher risk of frequent atrial ectopy and complex arrhythmias. This is further evidence that maintaining good physical fitness should be a priority for everyone to improve their heart health and prevent the development of arrhythmias later in life." Dr Moses continued. "Exercise should be tailored to one's age and capacity, and can involve simple and cheap activities such as walking, running, cycling or other aerobic activities performed consistently."
1,151 healthy individuals aged between the ages of 40 and 65, without any heart symptoms or structural heart disease,** took part in the study at the Institute for Medical Screening, Chaim Sheba Medical Center. Israel. The mean age of participants was 52 ± 7 years and 88% were men and 12% were female.
Participants' fitness and heart health were monitored during exercise stress testing using portable and continuous electrocardiography (ECG) that records the heart's electrical activity, also known as Holter monitoring.
This allowed researchers to look in detail at participants' heart health – in particular to detect irregular heartbeats, or arrhythmias, and identify whether they related to the ventricular or atrial heart muscles.
Researchers grouped participants by their 'median ectopy daily burden' which is the average percentage of premature or early heartbeats per day. They categorised the participants into having a low or high ectopy (irregular heartbeat) burden. They found that 32% of participants had supraventricular tachycardia, 4% had atrial fibrillation and 6% had nonsustained ventriculatachycardia – all of which are complex arrhythmias.
Univariate analysis revealed that 'high atrial ectopic burden' was associated with older age, male sex, lower fitness levels, high blood pressure and a measure of reduced kidney health. High ventricular ectopic burden was associated with older age and a measure of reduced kidney health – but was not related to fitness levels. Multivariable analysis confirmed that older age and lower fitness levels were strong, independent risk factors for atrial ectopy burden.
The researchers found that the chance of arrhythmia increased by 9% per year for atrial and 4% per year for ventricular arrhythmia. Age-stratified analysis demonstrated a marked rise in arrhythmia prevalence starting from the 50–54 age group.
"Our findings suggest that risk of arrhythmia begins to increase well before typical retirement age. They strongly support the need to screen older adults for arrhythmias, beginning at around age 50, to allow for timely intervention and improved long-term outcomes." Dr Moses said.
Atrial and ventricular arrythmias are commonly observed in healthy individuals and were often considered harmless. However, it is now thought that a higher burden of irregular heartbeats, or ectopy, might be a precursor of heart disease (1,2). As a result, there is a need to find new ways to identify risk factors in healthy individuals where interventions may address long term risks.
Dr Moses noted that more research is needed to confirm these findings, "As this is an observational study, we need to be careful about drawing conclusions about causation, and it is also important to note this study was conducted in a population that was not very diverse, particularly with regards to gender. Future research will be needed to tell us whether it is possible to intervene early to reduce the risk of arrhythmias using lifestyle changes, exercise programs or pharmacological treatments."
