Reps Guides
Recovery & HRV Guides
These are plain-English guides to the numbers behind recovery — HRV, readiness scores, and Apple Watch recovery signals. Each one explains what a metric actually means, how to read it against your own baseline, and how to turn it into a better decision about when to push and when to rest.
New to all of this? Start with What Is HRV, then find out whether your number is normal in HRV Normal Range by Age and what actually moves it in How to Improve Your HRV. From there, see how it all rolls up in What Is a Readiness Score. If you already wear a Whoop or Oura, How to Read Your Whoop or Oura HRV untangles why their numbers never quite agree.
Want a quick number instead? Try the free calculators for resting heart rate, VO2 max, caffeine, sleep, protein and training load.
What Is HRV (Heart Rate Variability)?
The beat-to-beat variation in your heart rhythm, what it says about your nervous system, and why trends against your own baseline matter more than any single number.
Read guideHRV Normal Range by Age and Sex
Average SDNN and RMSSD by age and sex from 1,906 healthy adults, a checker for your own number, and why your rolling baseline beats any age chart.
Read guideApple Watch HRV Explained
Apple Watch reports SDNN, not RMSSD. Why that makes its number look low next to Whoop, Oura or online charts, and how to read it.
Read guideHow to Improve Your HRV
Sleep, alcohol, aerobic base, slow breathing and honest recovery — the levers that actually move HRV, ranked, with how strong the evidence is behind each.
Read guideWhat Is a Readiness Score?
How readiness scores work, how products choose their inputs, and how Reps uses sleep, resting heart rate, and recent strain to guide when to push or back off.
Read guideHow to Read Your Whoop or Oura HRV
Why your Whoop and Oura HRV numbers don't match, what each device actually measures, and how to interpret the trend instead of chasing the figure.
Read guideStop interpreting numbers by hand
Let Reps turn sleep, resting heart rate, and recent strain into daily readiness
Reps brings health, nutrition, training, and recovery together on iPhone and Apple Watch — use one part of your day on its own or see the whole picture.
Free to download • Built for iPhone + Apple Watch