MAF 180 Heart Rate Calculator
Recovering from major illness, surgery, or on medication
Injured, inconsistent training, asthma/allergies, or getting sick often
Consistent training (up to 2 years) without injury or illness
Consistent training (>2 years) with improvement and competitive goals
Maximum Aerobic Function (MAF) HR:
0 bpm
Aerobic Training Zone:
0 – 0 bpm
* This is the heart rate range you should maintain for all aerobic base building workouts.
What is the MAF 180 Formula?
The MAF (Maximum Aerobic Function) method, developed by Dr. Phil Maffetone, is a heart rate training formula designed to build a massive aerobic base. Unlike generic formulas like "220 minus age," the 180 Formula is specifically tailored to determine the maximum heart rate at which your body relies primarily on fat for fuel (aerobic system) rather than sugar (anaerobic system).
How is MAF Calculated?
The calculation starts with the number 180 and subtracts your age. However, to get an accurate number, you must apply physiological adjustments based on your health and training history:
- Subtract 10: If you are recovering from a major illness (heart disease, operations, hospital stays) or are on regular medication.
- Subtract 5: If you have been injured, have regressed in training, get more than two colds a year, have allergies/asthma, or are inconsistent.
- Subtract 0: If you have been training consistently (at least 4 times a week) for up to two years without any of the problems listed above.
- Add 5: If you have been training for more than two years without problems and have made measurable progress in competition.
The Importance of the MAF Zone
Your calculated MAF number is the ceiling of your aerobic training zone. Your training range is typically 10 beats below this number up to the MAF number itself.
For example, if your MAF heart rate is 145 bpm, your training zone is 135–145 bpm. While training, you should not exceed 145 bpm. By staying strictly aerobic, you improve your body's ability to burn fat, reduce oxidative stress, and minimize inflammation.
Benefits of MAF Training
Runners, cyclists, and triathletes use this method to:
- Increase endurance without overtraining.
- Improve fat utilization for fuel.
- Prevent common overuse injuries.
- Ideally get faster at the same heart rate over time (aerobic deficiency syndrome correction).