Zone 2 Heart Rate Calculator

Zone 2 is steady, easy aerobic exercise held just below your first threshold, the point where blood lactate starts to rise above resting levels and your breathing first deepens. A panel of 14 sport scientists and coaches agreed on this definition in 2025¹. Few people know their own threshold, so this calculator estimates zone 2 in several ways and shows each one with its source.

What Zone 2 Heart Rate Measures

Your zone 2 heart rate is a range of beats per minute (bpm) that aims to land just under that first threshold. It does not measure fitness, fat burning or calories. The name "zone 2" also means different things in different zone systems, which is why one person can be given several different numbers.

The Formula

Max heart rate (Tanaka) = 208 - 0.7 x age

% of max HR, watch style = 60% to 70% of max HR

% of max HR, endurance scale = 75% to 85% of max HR

Heart rate reserve (Karvonen) = resting HR + 0.60 to 0.70 x (max HR - resting HR)

MAF ceiling = 180 - age, then -10, -5, 0 or +5

Lab anchor = 10 bpm below up to 1 bpm below your first threshold heart rate

Tanaka's max heart rate equation comes from 351 studies and 18,712 people², and the reserve method goes back to Martti Karvonen's 1957 study³.

How This Calculator Computes Your Result

Enter your age. Optional extras are your resting heart rate (counted in the morning before you get up), a measured max heart rate, which replaces the age estimate, and your first threshold heart rate from a lab test. Limits are rounded to whole bpm and match our Heart Rate Zone Calculator.

Each method gets its own row. The headline uses the most personal method you entered: lab threshold, then heart rate reserve, then % of max. An optional setting applies Phil Maffetone's MAF adjustments. Ticking the beta blocker box hides the age-based rows (see below).

What Your Result Means

This is how the methods compare for a 40-year-old with an estimated max of 180 bpm and a resting heart rate of 60.

MAF is a coaching rule, not a lab-derived formula: Maffetone says 180 minus age is not linked to VO2 max or lactate threshold⁶. A lab threshold beats every formula, because it is measured on you.

Zone 2 Heart Rate by Age

Max heart rate here is Tanaka's estimate. The reserve column assumes a resting heart rate of 60 bpm. Maffetone says his rule may need more individual adjustment after age 65⁶.

Why the Methods Disagree

Your first threshold is personal. In 100 adults tested in a lab, the lactate threshold fell anywhere from 60 to 90% of max heart rate⁷. In a treadmill study of more than 1,000 adults, the first ventilatory threshold averaged about 75 to 83% of measured max heart rate across groups, and it sat higher in fitter people and in women⁸. So 60 to 70% of max falls below most people's first threshold. With a resting heart rate of 60 and a max of 180, 60 to 70% of reserve equals 73 to 80% of max, which is why that method often lands near measured thresholds.

Max heart rate is the second problem. Even the best age formula in a study of 3,320 healthy adults had a standard error of 10.8 bpm⁹, and every percent-based row moves with that error. MAF ignores max heart rate, so it can land above or below the others.

Why Zone 2 Means Different Things in 3, 5 and 7 Zone Models

In the 3-zone model sport scientists use, zone 2 is the harder band between the first and second thresholds, which matches zone 3 of the 5-zone endurance scale⁵. The popular "zone 2" is the top of zone 1 there. In 5-zone systems, watch-style and endurance-scale zone 2 sit about 27 bpm apart for a max of 180, as the table above shows. In Joe Friel's 7 zones, zone 2 is 85 to 89% of lactate threshold heart rate (LTHR) for running and 81 to 89% for cycling¹⁰. LTHR is your average over the last 20 minutes of a 30-minute solo time trial and marks the second threshold, so a running LTHR of 165 gives a zone 2 of 140 to 148 bpm. Our Heart Rate Zone Calculator builds the full zone table for each model.

What Zone 2 Training Is For and How Much Time It Takes

The expert panel expected zone 2 work to improve the heart, circulation and muscles, but said these gains may also come from slightly easier or harder work¹. Much of the interest comes from elite endurance athletes, who train 15 to 30 hours a week, with about 80% of sessions mostly below the first ventilatory threshold⁵. A 2025 review argued this does not prove zone 2 is the best intensity for building mitochondria, and that harder efforts matter more when training time is short¹¹. For health, the WHO advises adults to get 150 to 300 minutes of moderate activity a week, 75 to 150 minutes of vigorous activity, or a mix¹². Zone 2 sessions are one way to fill the moderate part.

Check Your Range With the Talk Test

While exercising, read a paragraph of 30 to 100 words aloud and ask, "Can I speak comfortably?" The answer is yes, "yes, but" or no, and the test closely tracks the ventilatory thresholds in many groups, including people with chronic disease¹³. In zone 2 the answer is a clear yes. When talking first gets harder, you are near your first threshold, whatever your watch says.

Beta Blockers and Other Heart Rate Medicines

Beta blockers work partly by slowing the heartbeat¹⁴, so age-based rows stop fitting. In a trial of 71 men taking beta blockers after heart bypass surgery, percentages of peak heart rate could not separate the first and second thresholds well enough to set training limits¹⁵. Ticking the beta blocker box leaves the talk test and any threshold you enter, ideally one measured while taking your usual medicine. If you have a heart condition, your doctor can tell you which range fits you.