# Zone 2 Heart Rate Calculator — full text

Free tool at https://zone2calculator.com/. No signup. All calculation happens in
the visitor's browser; inputs are never uploaded or stored on a server (they may
be kept in the browser's own localStorage and in the page URL for sharing, both
wipeable by clearing browser data).

## What it does

Enter age (required, 10–100), optional resting heart rate (30–120 bpm, measured
first thing in the morning), and optional measured max heart rate (from a lab or
hard field test). The calculator shows the Zone 2 heart-rate range by three
methods side by side, all five training zones for the current max-HR basis, and
a weekly 150-minute training plan.

## The three methods

### 1. % of max HR (Tanaka)

Max heart rate = 208 − 0.7 × age (Tanaka, Monahan & Seals, 2001, "Age-predicted
maximal heart rate revisited", Journal of the American College of Cardiology
37(1):153–156). Zone 2 = 60–70% of max heart rate. Example: age 40 → estimated
max 180 bpm → Zone 2 = 108–126 bpm. Population average; an individual's true max
can differ by ±10–12 bpm.

### 2. Karvonen heart-rate reserve

Target = resting HR + intensity × (max HR − resting HR) (Karvonen, Kentala &
Mustala, 1957). Zone 2 = 60–70% of the reserve. More personal than Tanaka when a
real resting heart rate is known. Example: age 40, resting 60 → max 180,
reserve 120 → Zone 2 = 132–144 bpm. If no resting heart rate is given, the site
does not invent one — the Karvonen result is shown as needing the input.

### 3. Talk test

A field heuristic, not a formula: at Zone 2 you can speak in full sentences but
could not sing. The free reality check for any number a formula gives you.

### Five training zones

The widely used five-zone split of % max heart rate: Z1 50–60%, Z2 60–70%,
Z3 70–80%, Z4 80–90%, Z5 90–100%. On this site, zone colours follow the Garmin
standard (Z1 gray, Z2 blue, Z3 green, Z4 orange, Z5 red) and are used only where
they encode data.

## Weekly plan

At least 150 minutes of Zone 2 per week, in 3–5 sessions. Templates: 3 × 50
minutes, 5 × 30 minutes, 4 × 45 minutes (180 minutes, above the minimum).
Consistency beats any single perfect session. Practical starting references:
treadmill incline walking (~3 mph / ~5 km/h at 10–12% incline), easy-gear
cycling at 80–90 rpm on flat routes, rucking with ~10% bodyweight pack.

## Frequently asked questions

**How do I calculate my Zone 2 heart rate?**
Estimate your max heart rate with the Tanaka formula — 208 minus 0.7 times your
age — then take 60 to 70 percent of it. A 40-year-old gets an estimated max of
180 bpm, so Zone 2 is 108 to 126 bpm. If you know your resting heart rate, the
Karvonen method gives a more personal range.

**Which method is most accurate?**
A lab-measured max heart rate combined with the Karvonen heart-rate reserve
formula is the most accurate practical method. Tanaka's formula is a population
average — your true max can be 10 to 12 bpm off in either direction. The talk
test is the best free reality check for any number a formula gives you.

**What if I don't know my resting heart rate?**
Use the % of max HR method — it needs only your age. To get your resting heart
rate, wear your watch to bed or check your pulse for a full minute right after
waking, before getting up. Do it for a few mornings and take the average.

**Can I just walk for Zone 2?**
For many people, flat walking is too easy to reach Zone 2 — that's why incline
walking and rucking are so popular: they raise your heart rate without running.
If flat walking already puts you in range, that's perfectly fine Zone 2.

**How many minutes per week?**
Aim for at least 150 minutes per week across 3 to 5 sessions — for example
3 × 50 minutes, 5 × 30 minutes, or the popular 4 × 45 minutes (180 minutes,
above the minimum). Consistency beats any single perfect session.

**Do I need a chest strap?**
Not to start. A wrist-based optical sensor is fine for steady Zone 2 work. A
chest strap (like the Polar H10) is more accurate and responds faster to
changes — worth it once Zone 2 becomes a weekly habit.

## Honesty and limits

- Formula estimates are population averages, not personal diagnoses.
- Medications that affect heart rate (e.g. beta blockers) make these formulas unreliable.
- This is educational content, not medical advice. People with a heart condition,
  who are pregnant, or who have been told to limit exercise should consult a
  clinician before training by heart rate.

## Sources

- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited.
  J Am Coll Cardiol. 2001;37(1):153–156.
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a
  longitudinal study. Ann Med Exp Biol Fenn. 1957;35(3):307–315.
- Site privacy, formula citations and open-source credits:
  https://zone2calculator.com/about.html