Key Takeaways
- Zone 2 typically corresponds to 60–70% of estimated maximum heart rate — a conversational pace effort.
- This calculator provides three methods side-by-side: % of HRmax, Karvonen (Heart Rate Reserve), and MAF 180 Formula.[1][2]
- Different methods produce slightly different ranges — comparing them helps identify a practical target zone.
- The "talk test" is a simple subjective check: at Zone 2, you should be able to speak in full sentences with slight breathlessness.
What Is Zone 2 Training?
Zone 2 refers to a specific heart rate intensity band in the 5-zone training model. It falls in the range of approximately 60–70% of maximum heart rate and is typically described as a "comfortable" or "conversational" pace.
Common activities performed at Zone 2 intensity include easy jogging, brisk walking, relaxed cycling, and light swimming. It represents the effort level where you could sustain the activity for an extended period while still being able to hold a conversation.
Zone 2 is a commonly referenced intensity in endurance training frameworks. Its exact boundaries vary depending on the calculation method used, which is why this calculator shows multiple methods for comparison.[5]
Calculation Methods Explained
Method 1: Percentage of HRmax
Zone 2 = 60–70% of your estimated maximum heart rate. HRmax is estimated using one of three published formulas: Tanaka (2001), Fox/Haskell (1971), or Gellish (2007). You can also enter your own known HRmax.[1]
Method 2: Karvonen / Heart Rate Reserve
HRR = HRmax − Resting HR
Zone 2 = RHR + (HRR × 0.60) to RHR + (HRR × 0.70)
This method accounts for individual resting heart rate, making it more personalized. Requires a resting HR input.[2]
Method 3: MAF 180 Formula (Maffetone)
MAF HR = 180 − Age ± modifier
Developed by Phil Maffetone, this approach uses a simple age-based formula with modifiers based on training history and consistency. The aerobic zone is defined as MAF HR − 10 to MAF HR.[3]
HRmax Estimation Formulas
Maximum heart rate (HRmax) is typically estimated using age-based equations. The most commonly referenced formulas include:
| Formula | Equation | Source |
|---|---|---|
| Tanaka (2001) | 208 − (0.7 × Age) | Tanaka, Monahan, Seals[1] |
| Fox/Haskell (1971) | 220 − Age | Fox, Naughton, Haskell |
| Gellish (2007) | 207 − (0.7 × Age) | Gellish et al.[4] |
All age-predicted formulas have standard error of approximately ±10–12 BPM. For the most accurate results, use a directly measured HRmax if available.[5]
The 5-Zone Training Model
The 5-zone model divides exercise intensity into bands based on percentage of HRmax or Heart Rate Reserve:
| Zone | % HRmax | Intensity | Description |
|---|---|---|---|
| 1 | 50–60% | Very Light | Recovery, warm-up, cool-down |
| 2 | 60–70% | Light | Aerobic base, endurance |
| 3 | 70–80% | Moderate | Tempo, steady-state |
| 4 | 80–90% | Hard | Threshold, interval work |
| 5 | 90–100% | Maximum | VO2max, sprint, near-max |
Limitations & Context
This is an informational calculator that estimates heart rate training zones using published formulas and methods.
- Age-predicted HRmax formulas have a standard error of ±10–12 BPM, meaning actual HRmax can differ from the estimate.[1]
- Individual responses to exercise intensity vary. Zone boundaries are approximations, not fixed thresholds.[5]
- Factors like caffeine, temperature, altitude, sleep, and stress can influence heart rate during exercise.
- The MAF formula is a practical field method and has not been validated the same way as laboratory-derived thresholds.[3]
Frequently Asked Questions
Sources & References
- Age-Predicted Maximal Heart Rate Revisited. Tanaka H, Monahan KD, Seals DR. Journal of the American College of Cardiology (2001)
- The Effects of Training on Heart Rate: A Longitudinal Study. Karvonen MJ, Kentala E, Mustala O. Annales Medicinae Experimentalis et Biologiae Fenniae (1957)
- The Big Book of Endurance Training and Racing. Maffetone P. Skyhorse Publishing (2010)
- Longitudinal Modeling of the Relationship Between Age and Maximal Heart Rate. Gellish RL, Goslin BR, Olson RE, McDonald A, Russi GD, Moudgil VK. Medicine & Science in Sports & Exercise (2007)
- The Accuracy of Heart Rate-Based Zone Training Using Predicted Versus Measured Maximal Heart Rate. ACE Research. American Council on Exercise (2019)
- Heart Rate Threshold-Based Training: A Review of Current Evidence. Neufeld EV, Wadowski J, Boland DM, Dolezal BA, Cooper CB. International Journal of Sports Medicine (2019)
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Disclaimer: This tool is for informational and personal journaling purposes only. Results are estimates based on published formulas and may vary based on individual factors such as genetics, training history, and measurement technique.