Maffetone MAF Training Method
Age 40, MAF says 140 bpm. Your Garmin Zone 2 goes to 152. Run at 148 and MAF calls it a violation while your LTHR chart still says easy. MAF (Maximum Aerobic Function) caps aerobic running at one heart rate from the 180−age formula — same intent as Zone 2, simpler math, stricter ceiling.
The 180−Age Ceiling
Base MAF HR = 180 − age, then adjust: −10 if recovering from illness/injury or on HR-affecting meds; −5 if inconsistent or returning from a break; +5 only if competing regularly for 2+ years with progress and no issues. Compare with the Zone 2 Calculator and LTHR vs Max HR.
Worked Scenario: Age 40, Consistent Trainee
MAF = 140 bpm. Monthly test: same 5 km loop at exactly 140 bpm. Month 1: 28:40. Month 3: 27:10 at the same HR — aerobic progress without chasing pace. On hills, walk rather than spike to 155. Use a chest strap when possible (watch HR accuracy) and watch drift on longer MAF runs.
MAF can be too conservative for aerobically strong runners whose true Zone 2 (from LTHR) sits 8–15 bpm higher. It is also a poor sole system if you need frequent race-specific speed. Use MAF to break gray-zone addiction; graduate to LTHR ranges when the single number clearly under-shoots conversational aerobic work.
MAF vs LTHR Zone 2
- MAF: one ceiling, great for discipline; may feel artificially slow once fit
- LTHR Zone 2: individualized range (e.g. ~85–89% LTHR) after a field test
Neither replaces fixing max HR / LTHR in the watch. See Zone 2 Guide and Easy Pace Guide.
Progress Signals on MAF
Improving: monthly test pace at MAF HR gets faster; resting HR stable; less late-run drift. Stalling for 6–8 weeks despite consistency — check sleep, fueling, or whether optical HR is capping you artificially low. MAF is a ceiling, not a target to sit on every minute if true easy is lower.
Decision Rule
If you cannot stay conversational on “easy” days, train all aerobic runs at or below MAF HR for 6–8 weeks and prove progress with a monthly pace-at-MAF test. If pace-at-MAF is improving but MAF feels absurdly slow while LTHR Zone 2 is still conversational, switch to the LTHR range and keep the same honesty.