Hong Life CalculatorsUnderstanding the MAF 180 heart rate calculator — concept and principle
The MAF 180 formula, created by coach and author Phil Maffetone, gives a single heart rate ceiling for easy aerobic training. The idea is to do most runs, rides or swims at or below this number so that you build endurance while keeping stress low. Endurance athletes use it as a simple alternative to lab-tested zones, especially when starting base training.
How it is calculated
MAF heart rate = 180 − age + adjustment
Aerobic range = (MAF heart rate − 10) to MAF heart rate, in beats per minute (bpm).
The adjustment depends on health and training history:
- −10: recovering from a major illness, surgery or hospital stay, or taking regular medication.
- −5: injured, regressing in training or competition, often catching colds or flu, having allergies or asthma, or new to training or training inconsistently.
- 0: training consistently without those problems.
- +5: training for more than two years without those problems and improving in competition.
The principle
Maffetone built the rule from his experience testing athletes rather than from a physiological law. The number 180 has no special meaning on its own; subtracting age adjusts for the fall in heart rate response over the years, and the corrections lower the ceiling for anyone whose body is under extra stress. Training below the ceiling keeps intensity in a range where fat supplies a large share of energy and recovery is quick. Over weeks, the same heart rate should produce a faster pace, which shows improving aerobic fitness.
Worked example
- Inputs: age 35, adjustment 0 (training consistently).
- MAF heart rate = 180 − 35 + 0 = 145 bpm.
- Aerobic range = 145 − 10 to 145 = 135–145 bpm.
| Age | MAF heart rate |
|---|---|
| 8.75 | 171 |
| 17.5 | 163 |
| 26.2 | 154 |
| 35 | 145 |
| 43.8 | 136 |
| 52.5 | 128 |
| 70 | 110 |
How to read the result
Treat 145 as a ceiling, not a target to sit on, and stay mostly in the 135–145 band during aerobic sessions. Many people find they must slow down a lot at first, sometimes to a walk on hills. To track progress, repeat a "MAF test" every few weeks: run the same course at your MAF heart rate and note the pace. A faster pace at the same heart rate is improvement; a slower one can signal fatigue, illness or overtraining.
Common mistakes
- Picking a more generous adjustment than your situation justifies.
- Doing all training at MAF heart rate forever; most plans add harder sessions once a base is built.
- Ignoring heart rate drift on hot days or long efforts.
- Relying on an inaccurate wrist sensor.
Frequently asked questions
Why does the formula use 180?
It was chosen empirically by Maffetone to match the heart rates he observed in athletes, not derived from an equation.
Does it work for people over 60 or under 16?
Maffetone suggests adjusting individually at these ages. Very fit older athletes may use a higher number with guidance.
Is the MAF rate the same as zone 2?
They often land close together, but zone 2 is defined from max or reserve heart rate, while MAF uses age and health history only.
Sources: Philip Maffetone, The Big Book of Endurance Training and Racing, Skyhorse Publishing, 2010