What the 180 Formula is
Dr Philip Maffetone's method defines a single ceiling for maximum aerobic function (MAF): the highest heart rate at which you train almost purely aerobically, with minimal anaerobic stress. The base figure is 180 − age, then a modifier personalises it.
Subtract 10 if you are recovering from illness or surgery or on regular medication; subtract 5 if you are injury-prone, new to training, or training inconsistently; keep it as-is for two years of consistent, injury-free training; add 5 only if you have been competing for over two years, improving, and staying injury-free.
How to train with MAF
Keep almost all aerobic training at or below your MAF ceiling, the core range is roughly the ceiling minus 10 up to the ceiling itself. It will feel slow at first; that is by design. The payoff is a deeper aerobic base, better fat metabolism and lower injury risk.
Track progress with the MAF Test: after a warm-up, hold your MAF heart rate over a fixed distance and record your pace. Repeated every few weeks, your pace at the same heart rate should improve. A stall or reversal flags overtraining, poor nutrition, illness or life stress.
Strengths and criticisms
MAF's strength is its simplicity and its bias toward easy training, which most amateurs under-do. Its main criticism is that 180 − age is a population rule of thumb: for some athletes the resulting ceiling sits noticeably below or above their true aerobic threshold (LT1). If you have lactate or LTHR data, cross-check it.
Worked example
A 35-year-old who has trained consistently and injury-free for 2 years (modifier 0):
| Base (180 − age) | 145 bpm |
| MAF aerobic ceiling | 145 bpm |
| Aerobic training range | 135–145 bpm |
If they'd been injury-prone, the −5 modifier would set the ceiling at 140 bpm instead.
Frequently asked questions
Is the MAF 180 Formula too slow?
It feels slow at first, which is intentional. Many athletes find their MAF pace is far easier than their habitual training, revealing an under-developed aerobic base. With consistent work, pace at the same MAF heart rate improves over weeks to months as aerobic fitness builds.
How is the MAF heart rate different from Zone 2?
They overlap heavily. MAF defines a single aerobic ceiling (180 − age, adjusted) rather than a band, and it tends to sit at the upper end of a typical Zone 2. Both target easy aerobic training; MAF is simply a stricter, single-number version of the same idea.
Should the modifier ever be +5?
Only if you have trained consistently for more than two years, are still improving, competing, and have stayed injury-free. Maffetone deliberately makes +5 hard to qualify for, most athletes should use 0 or a negative modifier. When in doubt, choose the lower, safer ceiling.
Sources
- Philip Maffetone, The Big Book of Endurance Training and Racing. The 180-Formula for maximum aerobic function (MAF).