Heart rate zones, sized to you.
Slide to your age and I'll sketch your five zones from the classic rough rule.
estimated max: 185 BPM (220 − age — a population average, honestly ±10 or more for any one heart)
| zone | range | how it feels |
|---|---|---|
| Z1 gentle | a stroll; you could sing | |
| Z2 easy | conversational; full sentences, forever pace | |
| Z3 steady | short phrases only; pleasantly working | |
| Z4 hard | a word or two; you're counting the minutes | |
| Z5 flat out | no words; only seconds live here |
about that 220 minus age
It's a folk formula with a lab coat on. The real spread of maximum heart rates at any age is wide — two healthy fifty-year-olds can max out 20 BPM apart — and the rule doesn't know your fitness, your medication, or your genes. What it's good for is sketching zones that are roughly right for most people, which is genuinely useful, as long as nobody carves the numbers into stone. If your training gets serious, a proper field test (or a lab) beats any subtraction.
what the zones are actually for
Zones turn one number into a pacing language. The counterintuitive lesson hiding in them: most easy-feeling fitness is built in Z2, where you can still chat — and most beginners spend their runs accidentally in Z3–Z4, feeling heroic and getting tired instead of fit. The talk test in the table is the low-tech version of everything here: if you can speak in full sentences, you're in the easy zones, whatever any gadget says.