Heart Rate Zone Calculator
Karvonen method with Daniels, Friel, and Seiler training-system comparison
Inputs
yrs
bpm
bpm
Tanaka 2001 (recommended)
Important Notes
- Age formulas can be off by ±10-15 bpm; a measured max from a hard 5K effort is more accurate.
- Resting HR varies widely; elite runners can be in the 30s, while 60-70 is common for recreational runners.
- HRV, medication, caffeine, and temperature all affect daily heart rate. Use pace first and HR as context.
- Heart rate lags by 30-60 seconds, so pace is usually better for interval sessions.
Your Heart-Rate Metrics
Max HR
184 bpm
Tanaka 2001 (recommended)
HR Reserve
129 bpm
Max - RHR
Health Status
Good
RHR 50-60
VO2max Estimate
51
Uth-Sørensen
Daniels 5 Zones (VDOT System)
| Zone | %HRR (Karvonen) | HR Range | RPE | Use |
|---|---|---|---|---|
E Easy | 65-78% | 139-156 | 3-4 | Aerobic base, recovery, long runs |
M Marathon | 78-85% | 156-165 | 5-6 | Marathon race pace; progression runs |
T Threshold | 85-90% | 165-171 | 7-8 | Tempo / threshold work; lactate-threshold development |
I Interval | 90-95% | 171-178 | 9 | 3-5 minute intervals; VO2max development |
R Repetition | 95-100% | 178-184 | 10 | 200-400 m speed; neuromuscular work |
Note: R pace (Repetition) is for short 200-400 m reps. Heart rate responds too slowly to this intensity, often lagging 30-60 seconds, so in practice R sessions should be guided bypace rather than HR. The 95-100% HRR shown here is only the possible late-session peak while hitting that pace.
Training-System Comparison
| Intensity | Daniels | Friel 7 | Seiler 80/20 | Talk Test |
|---|---|---|---|---|
| Very easy | E | Z1-Z2 | Zone 1 (< LT1) | Can recite a poem |
| Easy | M | Z2-Z3 | Zone 1 | Can chat |
| Moderate | T | Z4 | Zone 2 (LT1-LT2) | Short phrases only |
| Hard | I | Z5a-Z5b | Zone 3 (> LT2) | Cannot speak |
| Max | R | Z5c | Zone 3 | Air hunger |
80/20 rule: keep roughly 80% of training in Zone 1 and 20% in Zone 2/3; avoid the moderate intensity rut.
Max HR Formula Comparison
| Formula | Method | Result at age 35 | Note |
|---|---|---|---|
| Tanaka 2001 | 208 - 0.7×age | 184 bpm | Most widely studied; recommended default |
| Gellish 2007 | 206.9 - 0.67×age | 183 bpm | Based on 908 adults |
| Traditional | 220 - age | 185 bpm | Traditional rule with weak origin and large error |
Research Basis
- Karvonen et al. (1957): introduced the Heart Rate Reserve method, improving on %MHR for people with low resting HR.
- Tanaka et al. (2001, J Am Coll Cardiol): proposed 208 - 0.7×age, generally more accurate than the 220 formula.
- Gellish et al. (2007, MSSE): proposed 206.9 - 0.67×age from 908 tests tracked longitudinally over 25 years in 132 people; common in fitness settings.
- Uth et al. (2004, Eur J Appl Physiol): VO2max ≈ 15.3 × MaxHR/RHR, a simple estimate.
- Seiler & Kjerland (2006): elite endurance athletes naturally cluster near an 80/20 distribution; too much Zone 2 can blunt adaptation.