Cardiovascular

Heart-rate variability

Emerging biomarkerAutonomic physiologyECG/wearablems

Beat-to-beat variation used to characterize autonomic physiology.

What it measures

Variation in intervals between normal heart beats.

Why it matters

Useful in autonomic and recovery research and some clinical contexts.

How to interpret it

Measurement protocol, posture, time of day and device strongly affect values.

Important limitations

Consumer-device metrics are not interchangeable; no universal longevity target exists.

Evidence status

Emerging biomarker

Promising contextual physiological measure, but longevity-specific clinical interpretation is not established.

Research & guidance

Original papers, validation studies, reviews and clinical guidance connected to this measurement.

systematic review / meta-analysis

Heart rate variability in the prediction of mortality: A systematic review and meta-analysis of healthy and patient populations

Neuroscience & Biobehavioral Reviews · 2022

Lower HRV was associated with higher mortality across diverse populations, but preventive-screening utility and standardized individual targets remain unresolved.

For education and evidence exploration, not diagnosis or individualized medical advice.