Why your zones might be wrong right now
Every heart rate zone — the "easy" zone 2 you're supposed to build your base in, the threshold zone, all of them — is calculated as a percentage of your maximum heart rate. Most calculators estimate that maximum from your age. But age formulas are population averages, and real max heart rate scatters about ten beats in either direction around them.
Ten beats is enough to push every zone boundary off by a full zone. The most common result: people run their easy days too hard without knowing it — training in zone 3 while believing they're in zone 2 — quietly undermining the aerobic base easy running is meant to build.
What the field test does
It's a short, structured hard effort that brings your heart rate to its true peak under controlled conditions, so you can read your actual maximum off your monitor instead of inheriting a formula's guess. You do it once. The number is good for a year or more. Then you plug it into any zone calculator and every zone rebuilds around your real physiology.
What's inside the guide
- Two field-test protocols — a track/treadmill version and a hill version, so you can use whichever setting you have.
- Exactly how to warm up, build, and finish — step by step, so you actually reach your true max instead of stopping short.
- How to read your result — what's normal, what to trust, and when to suspect the monitor instead of your heart.
- A gentler, non-maximal alternative if an all-out test isn't right for you.
Built on the same sports science behind the Moony Fitness heart rate zone calculator — no fluff, no filler, just the method.
Measure, don't guessReplace the age-formula estimate with your real, measured maximum heart rate.
Two ways to testTrack/treadmill or hill — whichever you can access. Both find the same number.
Accurate zones for goodPlug your number into the calculator and every zone rebuilds around you.