HRV for Recovery: How to Read Your Readiness Score
Heart rate variability is the most actionable objective recovery metric available to athletes and fitness enthusiasts. Here is what it measures and how to use it intelligently.
What HRV Measures
Heart rate variability measures the variation in time between consecutive heartbeats. A heart that beats at exactly 60 bpm is not producing 1000ms intervals consistently - it oscillates. Higher variability indicates the autonomic nervous system is functioning well, with parasympathetic tone dominant. Lower variability indicates sympathetic dominance - stress, illness, overtraining, or insufficient recovery.
Why HRV Predicts Recovery State
Training, illness, and stress all suppress HRV by elevating sympathetic nervous system activity. Recovery, sleep, and parasympathetic interventions restore it. Tracking your personal HRV baseline over time creates a personalised readiness score that is more reliable than subjective feel, which is easily overridden by motivation or routine.
"HRV does not tell you whether to train. It tells you how your body responded to the training you already did - and that information changes how you should programme the next session." - Marco Altini, HRV researcher
How to Track HRV Practically
- Morning measurement before rising, same time daily (supine, first 5 minutes of waking)
- Chest strap plus smartphone app (Polar H10 with Elite HRV) gives the most accurate readings
- Wrist-based devices (Apple Watch, WHOOP, Oura) are convenient but less accurate; use them for trends not absolute values
- A minimum 4-6 week baseline is required before the data becomes actionable
Interpreting HRV Readings
| Reading vs baseline | Recommended approach |
|---|---|
| 10%+ above baseline | High readiness - push harder, add volume or intensity |
| Within 10% of baseline | Normal - train as planned |
| 10-20% below baseline | Reduced readiness - moderate session, focus on technique |
| 20%+ below baseline | Low readiness - active recovery or rest day |
HRV and Recovery in Practice
HRV is most valuable as a trend tracker, not a daily pass/fail. A single low reading after a hard session is expected and not concerning. A persistently declining trend over 5-7 days signals accumulated stress that warrants a recovery week. Use it alongside subjective feel, not instead of it - sometimes they agree, and the combination gives you more confidence in the decision.
