Maximum Aerobic Function (MAF) is the ideal heart rate for all aerobic training. Below are excerpts from the Website of Dr. Phil Maffetone, creator of the MAF fitness metric.
The MAF 180 Formula
Subtract your age from 180, then modify from one of the categories below:
- If you have or are recovering from a major illness (heart disease, any operation or hospital stay, etc.), are in rehabilitation, are on any regular medication, or are in Stage 3 (chronic) overtraining (burnout), subtract an additional 10.
- If you are injured, have regressed or not improved in training (such as poor MAF Tests) or competition, get more than two colds, flu or other infections per year, have seasonal allergies or asthma, are overfat, are in Stage 1 or 2 of overtraining, or if you have been inconsistent, just starting, or just getting back into training, subtract an additional 5.
- If you have been training consistently (at least four times weekly) for up to two years without any of the problems mentioned in a) or b), no modification is necessary (use 180 minus age as your MAF HR).
- If you have been training for more than two years without any of the problems listed above, have made progress in your MAF Tests, improved competitively and are without injury, add 5.
- The MAF 180 Formula may need to be further individualized for athletes over the age of 65. For some, up to 10 beats may have to be added for those only in category (d) of the Formula. This does not mean 10 should automatically be added, but that an honest self-assessment be made.
- For athletes 16 years of age and under, the formula is not applicable; rather, an MAF HR of 165 has been used.
The MAF Test
The MAF Test can be done with any exercise except weight-lifting. The test can also be performed on stationary equipment such as a treadmill or other apparatus that measures power output.
To perform the test, you must first obtain your maximum aerobic heart rate with the help of the MAF 180 Formula. While working out at that heart rate, determine your walking, jogging or running pace—the time that it takes you to cover a certain distance—in minutes per mile, cycling speed in miles per hour, or repetitions (such as laps in a pool over time), and make a note of it. This is the parameter you will test for improvement later on.
During any MAF Test, your times should always get slower with successive repetitions: the first mile should always be the fastest, and the last should be the slowest. If that’s not the case, it usually means you haven’t warmed up enough.
The MAF Test should indicate faster times as the months go by. This means the aerobic system is developing and you’re burning more fat, enabling you to do more work with the same effort. Even if you walk or run longer distances, your MAF Test should show the same progression of results, providing you heed your maximum aerobic heart rate.
(Source: "What is the MAF Test?")