PulseMetric HRV

Understanding Heart Rate Variability (HRV)

Heart Rate Variability (HRV) is the physiological phenomenon of variation in the time interval between consecutive heartbeats (known as the RR interval). Unlike your resting heart rate, which counts the number of beats per minute, HRV measures the consistency of those beats. A higher HRV is generally associated with better autonomic nervous system balance, fitness, and stress resilience, while a consistently low HRV can indicate stress, fatigue, or potential health issues.

How to Use PulseMetric

This tool uses a logic-heavy manual input engine to calculate your metrics without the need for external sensors or webcams (which often suffer from permission issues).

1. Find your pulse: Place two fingers on your wrist (radial artery) or neck (carotid artery).
2. Sync & Tap: Once you feel a steady rhythm, tap the large red button exactly when you feel a beat.
3. Consistency is Key: Continue tapping for at least 15-20 beats (approx 15 seconds) to gather enough data for a statistical calculation.
4. Analyze: Click "Analyze Results" to process the timestamps through our algorithm.

Key Metrics Explained

• RMSSD (Root Mean Square of Successive Differences): This is the "gold standard" for short-term HRV monitoring. It strongly reflects parasympathetic (rest-and-digest) nervous system activity. Higher numbers indicate better recovery.
• SDNN (Standard Deviation of NN Intervals): A measure of overall variability. It reflects the ebb and flow of all factors influencing heart rate.
• Stress Score: A derived metric. When your heart beats like a metronome (low variability), your sympathetic (fight-or-flight) system is dominant, resulting in a higher stress score.

Interpreting Your Score

HRV is highly individual. Age, fitness level, and time of day all play a role. Generally, an RMSSD below 20ms is considered low (high stress/fatigue), while 50ms+ is considered healthy for most adults. Athletes often see scores above 100ms. Use this tool to track trends rather than focusing on a single absolute number.