Is Testosterone Linked to AFib? What we know

For their study, Tran and her team used data from the ASPREE clinical trial, a long-term study looking at the health effects of aspirin in older adults. They included 4,570 men with an average age of 74 years old with no history of cardiovascular disease (including AFib). The circulating testosterone concentration of the participants was measured at baseline. During an average follow-up period of 3 to 5 years, researchers found that 286 participants, or about 6%, developed AF.

They found that men who developed AFib had higher testosterone levels compared to those who did not. The average testosterone concentration in the men who developed AFib was 17 nmol/L compared to 15.7 nmol/L. They also tended to be current or former tobacco smokers and had a higher BMI at baseline. However, the association between testosterone and AF remained after controlling for these factors.

“Men’s sex has long been recognized as a risk factor for Afib, but it is difficult to determine whether that was directly due to the effect of testosterone, or simply other risk factors that are more common in men. This study found that higher testosterone levels carried a higher risk of (AFib), even when other clinical risk factors such as age, BMI, smoking and alcohol consumption were taken into account. This suggests a direct role for testosterone,” M. Ben Shoemaker, MD, director of the Atrial Fibrillation Precision Medicine Program at Vanderbilt University, told Healthline. Shoemaker was not involved in the investigation.

Another key finding of the study was that the association between testosterone concentrations and AFib was not linear. That means what they discovered isn’t as simple as: higher testosterone equals a higher risk of atrial fibrillation.

Men in the high-normal testosterone range had a higher risk of AFib, but so did men below the normal range.

“This study suggests that testosterone levels should be ‘just right,’” Shoemaker said.

Previous related studies have reached similar conclusions.

A 2017 study published in the Journal of the American Heart Association found that men with low testosterone had a higher incidence of AFib compared to men within a normal range. But when their testosterone levels were normalized through TRT, the prevalence of AFib dropped.

“Men with higher testosterone concentrations had a higher risk of atrial fibrillation, but there was no reduction in risk in men with lower testosterone. Our results suggest that staying within the mid-range of the clinical normal range would be best for lower risk of (AFib),” Tran said.

Despite the findings, the mechanism why testosterone outside the normal range is associated with AFib is still unknown.

“Originally, the focus was on testosterone’s role in regulating gene expression – a process that slowly increases the risk of (AFib) over time. It is now recognized that testosterone can bind directly to receptors in the heart that regulate its electrical activity, and those changes promote AFib,” Shoemaker said.

It is therefore important to keep testosterone within a healthy range due to the risk of AFib, but also for overall health.

Low testosterone, also called low T and testosterone deficiency, is defined as a concentration of less than 300 ng/dL, according to the American Urology Association. Testosterone production and circulating concentrations generally decrease with age.

Signs and symptoms of low T include:

• Low sex drive
• Erectile dysfunction
• Reduced muscle mass
• Increased body fat
• Low energy
• Smaller testicle and penis size

For individuals with low T, a doctor may prescribe TRT, or testosterone replacement therapy, to increase the circulating concentration of testosterone.

TRT is also often used off-label for various non-medical problems, such as gaining muscle mass, losing weight, and improving sexual performance. This is also popularly believed to be the case “anti-aging” properties. However, using TRT for these purposes may be illegal and of no scientific value.

Risks of high testosterone from TRT include:

• Acne
• High bloodpressure
• Difficulty urinating
• Shrinkage of testicles
• Fluid retention

“Recreational or unusual use of testosterone should be strongly discouraged. There are risks of harm, including heart-related complications in androgen abusers. Testosterone should only be prescribed to men with medical conditions requiring this treatment, with appropriate medical supervision and supervision,” Tran said.

In healthy older men, abnormal testosterone levels were associated with a greater risk of developing AFib, according to a new study.

The findings follow those of the 2023 TRAVERSE study, which found that men taking testosterone replacement therapy have a higher incidence of AFib, but no other cardiovascular disease risks.

Experts say that maintaining testosterone concentrations within a normal range — not too high and not too low — is optimal for minimizing the risk of AFib.