Heart Rate Zones (Zones 1–5)
What heart rate zones are
Heart rate zones divide your exercise intensity into 5 bands based on percentage of maximum heart rate (max HR). They provide a common language for workout intensity that applies across running, cycling, swimming, and rowing.
| Zone | Name | % Max HR | Feels like |
|---|---|---|---|
| 1 | Recovery / Easy | 50–60% | Light walk, can hold a full conversation |
| 2 | Aerobic base | 60–70% | Easy jog, comfortable conversation |
| 3 | Aerobic / Tempo | 70–80% | Moderate effort, short sentences only |
| 4 | Threshold | 80–90% | Hard, can speak a few words, uncomfortable |
| 5 | Maximum | 90–100% | All-out, cannot speak, unsustainable beyond 2–3 minutes |
Estimating max HR: 220 minus age is the standard formula (rough, population-average). More accurate: a maximum effort test (run a mile as fast as you can, note the peak HR).
Why zone 2 training matters (and why most apps ignore it)
Zone 2 — the “conversational” aerobic base zone — is where long-term cardiovascular fitness is built. Elite endurance athletes spend 70–80% of their training volume in zone 2.
Most workout apps push you into zone 3–4 for every session because it feels productive. In reality, chronic zone 3 training without zone 2 base building leads to plateau.
The exception: Peloton, Garmin, and Apple Fitness+ all have explicit zone 2 programming options. Garmin’s running coach includes easy-run prescriptions with HR ceiling alerts if you exceed zone 2.
How apps implement zones
Peloton App: zones display during class on the resistance/output meter. Instructors cue zone targets directly. Live class segments are structured around zone progressions.
Apple Fitness+: heart rate zones display on-screen during classes alongside the instructor, pulled from Apple Watch in real time. The on-screen ring colours map to zones.
Garmin Connect: customisable zone thresholds per activity type; alerts if you exceed target zones during coached runs; Training Status factors zone distribution into load assessment.
Strava: HR zone breakdowns in activity analysis for Premium users.
Whoop: doesn’t use zone terminology directly but the Strain score (0–21) maps roughly to zones — a Strain of 15+ corresponds to substantial zone 4 time.
The realism note
Zone calculations based on 220-minus-age can be significantly off for individuals. A 40-year-old with a real max HR of 195 bpm (not the formula-predicted 180) will be training in completely wrong zones if they use the formula.
If you’re serious about zone-based training: get a max HR test or use the Garmin algorithm (which estimates zones from outdoor run data over time). Don’t trust the formula.
Related concepts
- VO2 max — your zone 5 ceiling; higher VO2 max means faster pace at the same zone
- HRV — your daily readiness for zone 4–5 work
- Active recovery — zone 1 training; essential between hard sessions
- Resting heart rate — the baseline that determines where your zones start