Preliminary research has found that higher fitness levels reduced the risk of developing an irregular heart rhythm, or atrial fibrillation (AFib), by 30% to 50% in a study of Black male veterans, according to a press release from the American Heart Association (AHA).

“Engaging in physical activity to increase fitness is an inexpensive and practical intervention that health care professionals can prescribe to patients to prevent and manage cardiovascular disease,” said lead researcher Apostolos Tsimploulis, MD, in a press release. “All of our evidence suggests the health benefits associated with increased cardiorespiratory fitness and reduced risk of atrial fibrillation are the same for all adults regardless of race.”

According to the research, to be presented at the AHA’s Scientific Sessions 2020, AFib can lead to blood clots, stroke, heart failure, and other heart-related complications. AHA data have found that at least 2.7 million Americans are living with AFib.

To study the effects of exercise on the development of AFib, investigators examined the medical records of more than 11,000 middle-aged, Black, male veterans from 1985 to 2013. None exhibited evidence of heart disease during or prior to completing a symptom-limited treadmill stress test.

Participants were categorized into 4 fitness groups based on their age-specific cardiorespiratory fitness (CRF) levels, which were measured in metabolic equivalents of resting metabolic rate. The groups were categorized as least fit, moderately fit, fit, and highly fit.

Two independent investigators searched medical records to directly assess the association between CRF and AFib. Models were adjusted for risk factors, including heart or blood pressure medications, age, and body mass index.

During an average follow-up of 10.7 years, 1423 veterans developed AFib, with 16.6% in the least fit group, 10.9% in the moderately fit group, 11.9% in the fit group, and 12% in the highly fit group. When compared with the least fit group, the AFib risk was 29% lower in the moderately fit group, 37% lower in the fit group, and 51% lower in the highly fit group.

The investigators noted that the study results are strong based on the number of participants and AFib incidence was established during a follow-up period spanning approximately 17 years. Access to adjusted, longitudinal data permitted continuous follow-up and minimized the potential for disparities in medical care.

In the press release, Tsimploulis noted that the precise cause of AFib was not determined and CRF was only measured once. Furthermore, the level or frequency of physical activity was not assessed, and follow-up data on changes in CRF or physical activity of the participants over time were not available.

“We cannot make associations between atrial fibrillation and frequency, duration, or volume of physical activity,” Tsimploulis concluded. “Future studies are needed to document the effects of cardiorespiratory fitness on the incidence of atrial fibrillation, and the studies must include women.”

REFERENCE
Higher fitness levels linked to lower AFib risk in male, African American veterans [news release]. American Heart Association Scientific Sessions 2020; November 9, 2020. https://newsroom.heart.org/news/higher-fitness-levels-linked-to-lower-afib-risk-in-male-african-american-veterans?preview=ed44. Accessed November 10, 2020.