How to use HRV to guide your training
HRV (heart rate variability) is one of the strongest measurable predictors of recovery in endurance athletes. How to track it, read what it's telling you, and actually act on it.
By PulseLab ·
HRV (heart rate variability) measures the variation in time between heartbeats, not just the rate. When that variation is high and stable, your nervous system has recovered. When it drops, it hasn't, even if you feel okay.
The numbers back this up. Plews et al. (2013), published in the International Journal of Sports Physiology and Performance, split recreational endurance athletes into HRV-guided and fixed-plan groups across the same training block. The HRV group improved VO2max by 11.3%. The fixed-plan group improved 7.1%. Same hours, different outcomes.
Measure first thing in the morning before you get up. 60 to 90 seconds, chest strap if you have one, wrist device if you don't. The actual number matters less than you think. What counts is your personal baseline and how today compares to it. Track a 7-day rolling average and look for shifts, not day-to-day noise.
One low reading doesn't mean much. Two or three consecutive readings sitting 10% below your average is when to ease back. One high reading after a hard training block usually means you've absorbed the load and can push.
HRV alone doesn't tell the whole story. It won't pick up illness, life stress, or the fact your legs felt like concrete getting out of bed. That context matters too. In PulseLab, HRV accounts for 20% of the PULSE Score, the single largest input, combined with sleep quality, energy, soreness, and training load. Coach Zo reads all of it and adjusts your next session automatically.
Step-by-step guide
- 1.
Measure HRV consistently each morning
Take a 60-90 second HRV reading before you get out of bed. Use a chest strap (most accurate) or a compatible wearable such as Garmin, Whoop, Polar, or Oura. Consistency of timing matters more than the device.
- 2.
Establish your personal baseline
Track daily HRV for 2-4 weeks without changing training. Calculate a 7-day rolling average. This is your baseline. Individual HRV ranges vary enormously: a reading of 45ms can be low for one athlete and completely normal for another.
- 3.
Look for deviations from your baseline, not absolute numbers
A reading 10% or more below your 7-day average signals suppressed recovery. A reading 10% above suggests you have fully absorbed recent training load and are ready to push.
- 4.
Apply a simple decision rule
Single low reading: train as planned but watch effort. Two consecutive low readings: reduce intensity by one zone or shorten the session. Three or more: swap for easy aerobic work or rest. Single elevated reading after a hard block: go hard.
- 5.
Track HRV alongside subjective check-in
HRV alone misses stress, illness, and emotional fatigue. Combine it with a quick morning check-in (energy, soreness, sleep quality) for a more complete readiness picture. PulseLab's PULSE Score does this automatically. HRV is 20% of the score, subjective inputs cover another 45%.