MAF Heart Rate Zone Calculator
Calculate your Maximum Aerobic Function (MAF) heart rate using the Phil Maffetone 180 Formula.
Note: Always consult with a physician before starting a new exercise program.
What is the MAF Heart Rate?
The MAF (Maximum Aerobic Function) method, developed by Dr. Phil Maffetone, focuses on building a strong aerobic base by training at a specific heart rate. By staying below this threshold, your body learns to burn fat more efficiently as a primary fuel source, which improves endurance and reduces the risk of injury and overtraining.
How the 180 Formula Works
The 180 Formula is the cornerstone of the MAF method. Unlike the generic "220 minus age" formula, which estimates maximum heart rate, the 180 Formula calculates the maximum heart rate for aerobic training. Here is the step-by-step breakdown:
- Base Calculation: Start with 180 and subtract your age.
- Adjustment A (-10): If you are recovering from a major illness (heart disease, any operation, or hospital stay) or are on regular medication.
- Adjustment B (-5): If you are injured, have regressed in training or competition, get more than two colds or bouts of flu per year, have allergies or asthma, or if you have been inconsistent in your training.
- Adjustment C (0): If you have been training consistently (at least four times weekly) for up to two years without any of the problems mentioned in A and B.
- Adjustment D (+5): If you have been training for more than two years without any of the problems listed above, and have made progress in competition without injury.
Example Calculation
If you are 40 years old and have been training consistently for several years without injury (Category C):
180 – 40 = 140 BPM.
Your MAF training zone would be between 130 and 140 beats per minute. For maximum aerobic benefits, most of your training should occur within this 10-beat range.
Why Train at a Lower Heart Rate?
Training at a lower, aerobic heart rate might feel "too slow" initially, especially for seasoned runners. However, this method encourages physiological adaptations including:
- Increased Capillary Density: Better blood flow to the muscles.
- Mitochondrial Growth: Your cells become more efficient at producing energy.
- Fat Metabolism: Your body preserves glycogen stores and burns fat, allowing you to go longer distances with less "bonking."
- Reduced Stress: Lower heart rate training produces less cortisol, preventing burnout and keeping the nervous system balanced.