What is the MAF heart rate?
MAF stands for Maximum Aerobic Function. It is the approach developed by Dr Phil Maffetone, who coached triathlon legend Mark Allen and many other endurance athletes. The idea is simple: do most of your training at or below a heart rate where your body relies mainly on aerobic, fat-burning metabolism. Over time, your pace at that heart rate should improve — your aerobic engine gets bigger without the fatigue and injury risk of frequent hard running.
The 180 formula
−10 · recovering from major illness or surgery, or taking regular medication
−5 · injured, regressing in training or competition, frequent colds/flu, allergies or asthma, or just starting out or training inconsistently
±0 · training consistently (at least four times a week) for up to two years without these problems
+5 · training more than two years with progress in competition and no problems
If you are in doubt between two categories, Maffetone advises choosing the one with the lower heart rate. For athletes over 65 and under 16, he suggests some individual adjustment, ideally with professional guidance.
MAF heart rate chart by age
| Age | −10 | −5 | ±0 (base) | +5 | Training range (base) |
|---|---|---|---|---|---|
| 20 | 150 | 155 | 160 | 165 | 150–160 bpm |
| 25 | 145 | 150 | 155 | 160 | 145–155 bpm |
| 30 | 140 | 145 | 150 | 155 | 140–150 bpm |
| 35 | 135 | 140 | 145 | 150 | 135–145 bpm |
| 40 | 130 | 135 | 140 | 145 | 130–140 bpm |
| 45 | 125 | 130 | 135 | 140 | 125–135 bpm |
| 50 | 120 | 125 | 130 | 135 | 120–130 bpm |
| 55 | 115 | 120 | 125 | 130 | 115–125 bpm |
| 60 | 110 | 115 | 120 | 125 | 110–120 bpm |
| 65 | 105 | 110 | 115 | 120 | 105–115 bpm |
| 70 | 100 | 105 | 110 | 115 | 100–110 bpm |
| 75 | 95 | 100 | 105 | 110 | 95–105 bpm |
How to train with MAF
- Wear a chest-strap heart rate monitor and set an alarm at your MAF number.
- Run every easy session at or below MAF — most runners use a band of MAF minus 10 up to MAF.
- Slow down or walk whenever you go over, especially on hills and in the heat.
- Test monthly: run a fixed distance (for example 5 km on a track) at exactly your MAF heart rate and record the pace. If it is getting faster, your aerobic base is improving.
The MAF test. Maffetone recommends a regular MAF test: warm up, then run several miles or kilometres at your MAF heart rate and record each split. Progress shows up as faster splits at the same heart rate. If progress stalls for weeks, look at sleep, stress, diet and whether you are running too many hard sessions.
Is MAF right for you?
Great for
New runners, those returning from injury, marathoners and ultrarunners building a big aerobic base, and anyone who always runs too hard.
Watch out for
A formula cannot know your individual physiology. Some runners’ true aerobic threshold is well above or below 180 − age.
Faster work
Maffetone suggests adding hard training only after a solid aerobic base period; many coaches combine a MAF-style base with a small amount of faster work.
Measure progress
Use pace at a fixed heart rate, not how you feel, to judge whether the base period is working.
Compare your MAF number with a percentage-based range using the Zone 2 heart rate calculator, see all five zones in the heart rate zone calculator, and estimate your aerobic capacity with the VO2max calculator.
- Maffetone P. The Big Book of Endurance Training and Racing. Skyhorse Publishing, 2010.
- Maffetone P. The MAF 180 Formula. philmaffetone.com.
Last reviewed: September 2026 · Health disclaimer