An extra hour of physical activity every week may lower a person’s chance of developing the most common type of arrythmia by 11%, a new study shows.
Led by researchers at New York University (NYU) Langone Health (New York, USA), the study focused on atrial fibrillation (AF), which—if left untreated—can result in stroke, heart failure, and other health issues. According to the authors of the present study, while past investigations have linked exercise to a reduced risk of this type of arrhythmia, nearly all of these analyses have relied on participants’ often-inaccurate estimates of their own activity levels.
To avert this potential flaw, the NYU study team used data recorded from the fitness tracker Fitbit to objectively measure physical activity in more than 6,000 men and women across the USA. The results showed that those with higher amounts of weekly physical activity were less likely to develop AF and, notably, even modest amounts of moderate-to-vigorous exercise—ranging from taking a brisk walk or cleaning the house to swimming laps or jogging—were associated with reduced risk.
Study participants who averaged between 2.5 and five hours per week, which is the minimum amount recommended by the American Heart Association (AHA), showed a 60% lower risk of developing AF, while those who averaged greater than five hours had a slightly greater reduction of 65%.
“Our findings make clear that you do not need to start running marathons to help prevent atrial fibrillation and other forms of heart disease,” said study senior author Sean Heffron (NYU Langone Health, New York, USA). “Just keeping moderately active can, over time, add up to major benefits for maintaining a healthy heart.”
Heffron also noted that, in the only prior study that used activity monitors to investigate AF, researchers provided Fitbit-style monitors to the participants and tracked them for just one week, which may not accurately capture a person’s normal workout habits. However, this new investigation—which, according to the authors, is the largest of its kind to date—assessed participants for a full year and included only those who already owned the monitoring devices.
For the study, researchers analysed data collected as part of the All of Us programme—a National Institutes of Health (NIH) initiative designed to include Americans who have historically been underrepresented in medical research, such as racial minorities, women, and those who live in rural areas. For the programme, hundreds of thousands of participants completed questionnaires, gave blood samples, and had their physical measurements recorded, with their health tracked over time.
From that group, the study’s investigators assessed physical activity in a subset of some 6,086 people who used a Fitbit device, and permitted their Fitbit and electronic health records to be linked to their All of Us data. Researchers tracked activity information for a year as a baseline and then followed up for another five years to identify those who were diagnosed with AF. They also took into account factors known to contribute to the condition, such as age, sex and history of high blood pressure.
“These results highlight the value of Fitbits and similar monitors in medical research,” said study lead author Souptik Barua (NYU Grossman School of Medicine, New York, USA). “By offering an objective way to measure exercise for years at a time, these tools can provide deeper insight into how different patterns of activity can impact health.”
Barua added that, for example, the research team next plans to explore whether working out in the morning or at night may have different effects on heart health.
However, he also cautioned that—as many Fitbit owners in the study were college-educated white women—the investigation assessed a less diverse group than that of the overall All of Us population. The programme is now providing free devices to participants in underrepresented communities for future investigations. Another point made by Barua is that the study was not designed to tell whether exercise alone directly reduced the risk of AF, nor to detect how that might come about or what other factors—such as income or educational status—might be in play in reducing risk.
Nevertheless, the researchers concluded that the association between exercise ‘doses’ and the development of AF in the study participants was strong.
A report on these findings is set to be presented at the upcoming AHA Scientific Sessions (16–18 November, Chicago, USA).
