What is a good HRV score for a man in his 40s?

For men aged 40–49, a healthy HRV (measured as RMSSD during sleep) falls between approximately 35–55 milliseconds, values above 50 ms indicate strong cardiovascular fitness, and values below 25 ms warrant clinical attention (Shaffer & Ginsberg, Front Public Health, 2017).

HRV is age-dependent, sex-dependent, and highly individual. A 25 ms reading that alarms a 35-year-old is typical in an unfit 50-year-old. Published normative data from large cohort studies places average male RMSSD in the 30–45 ms range for men aged 40–49, but top-quartile aerobically fit men in this decade can have RMSSD above 60 ms. The device you use also matters: optical wrist HRV sensors (Whoop, Oura ring) have good agreement with ECG-derived RMSSD during sleep, but readings during active movement have lower accuracy (Shaffer & Ginsberg, Front Public Health, 2017).

Honesty Scale: Solid (1) for age-referenced ranges derived from cohort data. The specific number that triggers clinical concern varies by individual baseline, the trend matters more than any single reading.

What to do: Establish your personal 90-day baseline before deciding your number is "low." Compare your number to your own history, not to a 25-year-old's range. If your number is consistently below 25 ms AND you have cardiovascular risk factors (smoking history, family history, hypertension, diabetes), discuss with a cardiologist.

For the full picture, read Your Whoop Is Worried. Here Is What It Actually Found.