Estimating Aerobic Threshold MAF 180 Formula

estimating aerobic threshold

Every endurance athlete should know what the aerobic threshold is and spend most of their training time below that threshold. One way to measure intensity is with a heart rate monitor. Estimating Aerobic Threshold (AeT) using the MAF (Maximum Aerobic Function) 180 Formula will give you a conservative threshold heart rate. The MAF Formula was extensively researched and developed by Dr. Phil Maffetone in the early 1980s. Unlike the popular 220-age formula, it takes health and fitness factors into account.

Estimating Aerobic Threshold using the MAF 180 formula has two easy steps.

Step 1: Subtract your age from 180.

Step 2: Modify the number from Step 1 based on health and training history.

  • If you have or are recovering from a major illness/injury (heart disease, any operation or hospital stay, etc.) or are on any regular medication, subtract 10.
  • If you are injured, have a medical condition, get two or more colds or flus per year, have allergies or asthma, or are just getting back into consistent endurance training, subtract 5.
  • If you have trained consistently (at least 4 times per week) for up to two years without any of the problems above, keep the number the same (180 minus your age).
  • If you have trained for more than two years without any of the problems listed above and have progressed without injury, add 5.

Take the number obtained in Step 2 and use that as the upper limit heart rate for aerobic training.


45 year old athlete who is just getting back into endurance training.


For the athlete in the example above, training within a heart rate range of 10-15% of 130 (13-20 beats or 110-130) will give a good estimate to stay in the aerobic zone. This will build endurance and keep the intensity low enough to train/exercise more often while reducing the chance of injury.

Next weeks article will go into how to assess if you are below your aerobic threshold using the talk test. This test doesn’t require a heart rate monitor and is an effective way to check your intensity when you are in the backcountry.