Testosterone Therapy Effects on Resting Heart Rate and Heart Rate Variability
Testosterone therapy has been associated with small increases in measured heart rate on ambulatory monitoring in randomized trials. [1] Testosterone therapy has been associated with improved HRV metrics in at least one randomized controlled trial using 24-hour Holter monitoring. [2]
Resting Heart Rate and Ambulatory Heart Rate Findings
Randomized trial data using ambulatory blood pressure monitoring and simultaneous heart-rate measurement have shown small increases in 24-hour ambulatory heart rate after oral testosterone undecanoate exposure. [1]
- Small increases in ambulatory heart rate were observed after 120 days (0.7 beats/min) and 180 days (1.9 beats/min). [1]
Heart Rate Variability Findings
A controlled clinical trial in men with metabolic syndrome and testosterone deficiency (TDS) reported improvements in multiple HRV parameters after 9 weeks of intramuscular testosterone therapy. [2]
- Testosterone supplementation increased SDNN, SDANN, total power (TP), low-frequency (LF), ultra-low-frequency (ULF), and very-low-frequency domain measures. [2]
- HRV parameters in the treated group remained below those observed in healthy controls. [2]
Clinical Interpretation of Resting HR Versus HRV
Resting heart rate was not consistently reported as an outcome across testosterone trials measuring autonomic function. [1], [2] Ambulatory heart rate changes may not directly equate to strictly defined “resting” heart rate, even when captured during monitoring periods. [1]
Evidence Limitations
The available randomized evidence for HRV includes small controlled trials with specific populations and HRV endpoints. [2] The available randomized evidence for heart rate increases includes ambulatory monitoring studies with modest effect sizes. [1]
Practical Monitoring Implications
Assessment of cardiovascular and autonomic status during testosterone therapy should include heart-rate monitoring during routine follow-up. [1] HRV assessment is not standard clinical practice and should be interpreted using the specific device and HRV methodology used in research or specialized care settings. [2] Endocrine and cardiovascular safety monitoring should also account for known testosterone-related effects that may secondarily influence heart rate and autonomic balance (for example, hematocrit changes and blood pressure changes), which can confound interpretation of HRV and heart-rate trends. [1]
Safety Signal Context
Large randomized cardiovascular safety trials primarily evaluated major adverse cardiovascular events rather than HRV as a primary outcome. [3]
Bottom-Line Evidence Summary
Testosterone therapy can cause small increases in ambulatory heart rate in randomized trials. [1] Testosterone therapy can improve HRV metrics in some randomized controlled populations measured by 24-hour Holter monitoring. [2]
Sources for Further Reading
Key trials directly assessing HRV and ambulatory heart rate changes after testosterone therapy are available. [1], [2]