Testosterone Levels Linked to Atrial Fibrillation Risk in Men

What the Review Found About Testosterone and Heart Rhythm

A review published in the Journal of the Endocrine Society found that men with either low or high testosterone levels may face a higher risk of atrial fibrillation, a common type of irregular heartbeat.

The review examined existing studies and laboratory evidence, concluding that the relationship between testosterone and atrial fibrillation risk appears to follow a U-shaped curve. This means the risk is lowest for men whose testosterone falls in the middle of the normal range.

How the Evidence Was Gathered and Who It Applies To

The review is a narrative summary, not a meta-analysis, and draws on large population studies and recent laboratory research. The findings are based on observational data and laboratory models, not on prospective clinical trials.

The conclusions apply to adult men, especially those considering or currently using testosterone replacement therapy. The review does not establish cause and effect but highlights patterns seen in available evidence.

Implications for Men Managing Hormones and Heart Health

For men who need testosterone replacement therapy, the review suggests aiming for total testosterone levels in the middle of the normal range, approximately 350–550 ng/dL. Both low and high levels may increase the risk of atrial fibrillation through different biological mechanisms.

The authors recommend steady-release formulations, structured monitoring, and addressing other risk factors like obesity, sleep apnea, hypertension, and alcohol use. Monitoring should include heart rhythm, hematocrit, blood pressure, and kidney and liver function.

• Use calculated free testosterone if Sex Hormone-Binding Globulin (SHBG) is abnormal.
• Prefer stable (long-acting) testosterone formulations for men with heart or rhythm risk.
• Keep hematocrit in the normal range to limit dose.

Limitations and What to Consider Before Making Changes

The review is interpretive and summarizes existing literature, not a new clinical trial. The suggested therapeutic range for testosterone is based on observational data and has not been tested in prospective studies.

The relationship between testosterone and atrial fibrillation is complex, and individual factors may affect risk. Anyone considering changes to hormone therapy should consult a clinician and discuss personal risk factors.