Key takeaways
The MAF heart rate is 180 minus your age, adjusted by minus 10 to plus 5 for health and training history, and used as a ceiling for aerobic runs
There is little direct research on the method, and Maffetone's own 2020 review says the link to outcomes must still be verified scientifically
MAF is a simple way to keep easy running easy, but on its own it lacks the high-intensity work that most raises VO2max
MAF training (maximum aerobic function) is Phil Maffetone's heart-rate method: run at or below a ceiling of roughly 180 minus your age, and let your pace at that heart rate improve over months. It has a loyal following, especially among ultrarunners and triathletes. Here is what the formula is, what evidence exists, and how it compares with zone 2 and polarised training.
What is MAF training?
On his website, Maffetone describes developing the formula in the late 1970s and early 1980s by correlating athletes' heart rates with their mechanical efficiency and manual assessments, settling on the final version in the early 1980s. Going above the MAF heart rate, he writes, indicates a rapid transition towards anaerobic work.
The method is more than a number. His 2020 review with Paul Laursen frames it as part of a wider lifestyle programme aimed at raising fat oxidation to reduce excess body fat, prevent disease and improve performance. Progress is tracked with a repeat run at the MAF heart rate (the "MAF Test") to see whether pace improves.
MAF training heart rate: the 180 formula
From Maffetone's site, start with 180 minus your age, then adjust:
| Category | Who it applies to | Adjustment |
|---|---|---|
| A | Major illness or recovery from it (heart disease, operation, hospital stay), rehabilitation, regular medication, chronic overtraining | −10 |
| B | Injured, regressed or not improving, more than two colds or flu a year, allergies or asthma, overfat, early overtraining, inconsistent, just starting or returning | −5 |
| C | Training consistently (at least four times a week) for up to two years without the problems above | 0 |
| D | More than two years of training without the problems above, improving in MAF Tests and competition, uninjured | +5 |
Two exceptions: athletes over 65 in category D may add up to 10 beats, and under-16s use a fixed 165.
Example: a consistent 40-year-old runner gets 180 − 40 = 140 bpm as the ceiling for aerobic runs.
What the evidence says
Very little research tests MAF directly. We found no controlled trial comparing MAF training with another approach. The main peer-reviewed paper is Maffetone and Laursen's 2020 review in Frontiers in Physiology, which describes the heart rate as associated with maximal fat oxidation and usable without lab tests, and then states plainly that the relationship between training at this heart rate and laboratory measures, health outcomes and performance must be verified scientifically.
Some indirect evidence is relevant:
- Easy volume works. Seiler's review of successful endurance athletes found about 80% of sessions at low intensity, which MAF enforces (80/20 polarised training).
- But intensity matters for VO2max. In Helgerud's 2007 trial, intervals at 90–95% of max heart rate raised VO2max by 5.5–7.2% in 8 weeks, while the same total work at 70% of max heart rate did not raise it significantly (HIIT vs steady cardio).
- Age formulas are blunt. Any heart rate rule based on age alone can be well off for an individual, because max heart rate varies widely at a given age.
MAF training vs zone 2
Using the Tanaka formula for max heart rate (208 − 0.7 × age), here is where the MAF ceiling falls compared with a common 60–70% zone 2 range. This is our arithmetic, for category C runners:
| Age | MAF ceiling | Estimated max HR | MAF as % of max | Zone 2 at 60–70% |
|---|---|---|---|---|
| 25 | 155 | 190 | 81% | 114–133 |
| 35 | 145 | 184 | 79% | 110–128 |
| 45 | 135 | 176 | 76% | 106–124 |
| 55 | 125 | 170 | 74% | 102–119 |
| 65 | 115 | 162 | 71% | 98–114 |
So MAF is a ceiling, often above a percentage-based zone 2, and closer to it for older runners. Zone definitions differ between models (heart rate zone models compared); the most reliable way to place your own easy zone is a lab or field test of your first threshold. In practice, both approaches aim at the same thing: running that stays comfortably aerobic. More in zone 2 training and VO2max, or set your own numbers with the heart rate zone calculator.
MAF vs polarised training
Polarised training keeps most sessions easy and puts the rest well above threshold. In Stöggl and Sperlich's 9-week study in 48 well-trained endurance athletes, the polarised group improved VO2peak by 11.7%, more than groups doing high volume, threshold or high-intensity training alone. A strict MAF phase is effectively the high-volume arm of that study: easy work only. MAF tends to work best as the base phase of a polarised year, not as the whole year.
MAF training plan
Maffetone prescribes a heart rate, not a set plan. A practical 12-week version for a recreational runner:
| Weeks | Easy runs | Harder work | Check |
|---|---|---|---|
| 1–4 | 3–5 runs at or below MAF, walk hills if needed | None | MAF Test in week 1 |
| 5–8 | Extend long run by about 10 minutes a week | Strides after 1–2 runs | MAF Test in week 5 |
| 9–12 | Easy days stay at or below MAF | 1 session a week, e.g. 4 × 4 min at 90–95% HRmax | MAF Test in week 9, race or time trial in week 12 |
Expect to run slowly at first. If pace at your MAF heart rate stalls for weeks or gets worse, Maffetone treats that as a sign of too much stress; see also overtraining syndrome signs.
Who MAF training suits
- Good fit: beginners and returners who run every easy run too hard, injury-prone runners, ultra and Ironman athletes who need large volumes of easy work.
- Less ideal alone: runners chasing a faster 5k or marathon who need some VO2max work. See marathon training and VO2max for how to add it, and treat single-session predictors such as Yasso 800s as rough checks.
You can check whether your VO2max moves after a MAF block with the VO2max running calculator using a race or time trial.
Safety: this is general information, not medical advice. If you take medication that affects heart rate, such as beta blockers, heart-rate formulas will not apply; talk to your doctor before starting a training programme.
Frequently asked questions
What is MAF training?
A method developed by Phil Maffetone in which you keep most or all runs at or below a heart rate ceiling of 180 minus your age, adjusted for health and training history, to build the aerobic base before adding harder work.
How do you calculate MAF training heart rate?
Subtract your age from 180. Subtract 10 more after major illness, surgery or on regular medication, 5 more if injured, often ill or just starting, add nothing if training consistently, and add 5 after more than two years of steady progress.
Is MAF training the same as zone 2?
Not quite. For most adults 180 minus age works out at about 71 to 81% of estimated max heart rate, higher than the common 60 to 70% zone 2 range, so MAF acts as a ceiling rather than a zone.
Is there a MAF training plan?
Maffetone prescribes a heart rate rather than a fixed plan. A typical approach is several weeks of all easy running at or below MAF, then adding one harder session a week while easy days stay under the cap.
Sources
- Maffetone P. The MAF 180 Formula: heart-rate monitoring for real aerobic training. philmaffetone.com
- Maffetone P, Laursen PB. Maximum aerobic function: clinical relevance, physiological underpinnings, and practical application. Front Physiol, 2020. PubMed
- Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform, 2010. PubMed
- Helgerud J, Høydal K, Wang E, et al. Aerobic high-intensity intervals improve VO2max more than moderate training. Med Sci Sports Exerc, 2007. PubMed
- Stöggl T, Sperlich B. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Front Physiol, 2014. PubMed
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol, 2001. PubMed