The HRV Number You're Probably Misreading

MUSINGS FROM A COACH - 21 APRIL '26

With wearables, monitors and even mattress sensors becoming more and more common and accessible, there’s a chance that many of us have access to Heart Rate Variability (HRV) data. And many of us in the endurance world probably track our HRV. But there's a good chance some of us are using the data wrong — and on the mornings it matters most, that misread could cost us.

Here's the mistake: treating our daily HRV score like a green light or a red light.

We wake up, check our app, see a number. It's down from yesterday. We panic, skip the hard workout and spend the day second-guessing our training block. Or the number is up, so we hammer, even though we've been hammering all week.

That's not how HRV works.

HRV measures the variation in time between our heartbeats. A higher score generally indicates our autonomic nervous system is in a recovered, parasympathetic state. A lower score suggests sympathetic activation indicating our body is still processing stress, whether from training, poor sleep, illness, or life.

But here's the key word: our autonomic nervous system. HRV scores are not comparable between athletes. A score of 55 might be excellent for one person and concerning for another. Population averages are nearly useless for individual training decisions.

One number tells us almost nothing. Thirty numbers tell us everything.

What we’re looking for is our personal baseline: our rolling 7 to 14-day average and how today's score sits relative to that line. A single low reading inside our normal range is probably just noise (insignificant). However, three consecutive readings trending downward is a signal. That's the pattern that warrants adjusting our training load. Most HRV apps now show this trend line automatically.

A sustained downward trend doesn't automatically mean we’re overtrained. It means accumulated stress is exceeding our current recovery capacity. The stress could be training. It could also be poor sleep, travel, illness, work, or life. HRV doesn't know the difference.

The question isn't, "Should I skip today's workout?" It's, "What is the total stress load right now, and is today's session adding value or just adding fatigue?"

Here’s a suggested framework to help us make those decisions:

• Single low reading, within normal range: Train as planned. Monitor.

• Single low reading, well below baseline: Consider reducing intensity, keep the session. Note any non-training stressors.

• 3+ day downward trend: Reduce overall load. Prioritize sleep and nutrition. Discuss any upcoming intensity sessions with our coach (If no coach, consider ditching those intensity sessions). Monitor.

• Sustained suppression over 7+ days: Something systemic is happening and rest is probably best course of action.

Sometimes our training intentionally drives us into multi-day stress loads. When that happens, we can expect those trends in HRV. But when training doesn't intentionally do that, it may be time to act.

HRV is one of the best recovery tools available to endurance athletes. But it rewards patience and pattern recognition - not daily score-watching.

Gratefully,

Mark

CEO Team MPI