The Basic Framework
Your morning HRV reading tells you how recovered your nervous system is. A reading above your baseline suggests you're ready for intensity. A reading below suggests you might benefit from an easier day.
This isn't about avoiding training—it's about matching intensity to capacity. Research shows that athletes who adjust training based on daily HRV readings achieve better fitness gains than those following fixed plans—because they train hard when ready and recover when needed.
How it works in practice: Each morning, your device or app compares today's reading to your rolling baseline (usually 7-30 day average). The gap between today and your baseline is what matters, not the absolute number. A reading 10-15% above baseline means your nervous system is primed. A reading 10-15% below means something is taxing your recovery—possibly yesterday's workout, poor sleep, alcohol, stress, or early signs of illness.
Interpreting Your Score
Most apps provide a normalized readiness score (like 1-10 or a color code) that accounts for your personal baseline. This is more useful than raw RMSSD because it's contextualized to you.
Green/High (HRV at or above baseline): - Full capacity for high-intensity training, competitions, or PRs - Your nervous system has recovered from recent stress - Great day for intervals, heavy lifts, tempo runs, or match play - Example: Your 7-day average is 55ms RMSSD, today you're at 60ms
Yellow/Medium (HRV within normal fluctuation): - Standard training is fine—follow your plan as written - Maybe skip the hardest intervals or reduce volume by 10-20% - Most of your training days should fall here - Example: Your 7-day average is 55ms, today you're at 50-55ms
Red/Low (HRV significantly below baseline): - Reduced capacity—your body is recovering from something - Focus on easy movement: walking, yoga, light mobility work - Try breathing exercises or meditation - Don't push through multiple red days in a row—that's a path to overtraining - Example: Your 7-day average is 55ms, today you're at 38ms
Context matters: Look at the previous 3-5 days, not just today. A single green day after a week of reds doesn't mean you're fully recovered.
Don't Be a Slave to the Number
HRV is one data point, not a command. Consider:
- How do you actually feel?
- What does your training plan call for?
- Is this a one-day dip or a multi-day trend?
A single low reading shouldn't cancel an important workout. A week of declining HRV with increasing fatigue definitely should. Learn to interpret your data alongside how you feel.
Building Your Baseline
You need 2-4 weeks of consistent morning readings to establish a meaningful baseline. During this time, measure every day even if the insights aren't actionable yet. Your app needs data to learn your patterns.
During your baseline period: - Measure at the same time, same position, same conditions every morning - Don't make major lifestyle changes yet—you want to capture your current state - Log relevant factors: sleep quality, alcohol, training intensity, stress, travel - Expect readings to bounce around—that's normal. Your app will smooth this into a baseline.
Common pitfalls: - Poor sleep is the most common reason for unexpectedly low morning readings - Weekend vs. weekday patterns often reveal stress or alcohol effects - Skipping days creates gaps that weaken your baseline - Changing devices or apps mid-baseline requires starting over (different algorithms, different scales)
After your baseline is set, start making one change at a time and observe how your HRV responds over 1-2 weeks. This is how you learn what actually moves the needle for your body.
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