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MAF Training: A Guide to Low Heart Training

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MAF training focuses on improving your aerobic system by training at a specific heart rate. It's a popular training method that can give a much-needed boost to improve an athletes overall running ability.

When training with the MAF method, athletes use their heart rate to ensure their run is in the proper aerobic zone. This article will show you how and explain what you need to know about this very popular method of training.

Runner checking heart rate monitor

What is MAF Training?

MAF training focuses on running at or below your MAF heart rate ceiling in order to improve your body's aerobic function and ultimately increase your fat burning capability. 

This type of training was developed by Dr Phil Maffetone in the 1980s. But don't let that fool you, it is still a very popular training method.

Maximum Aerobic Function (MAF) focuses on 3 factors to improve your aerobic system, which is the fat-burning engine responsible for fueling your body: 

  1. Exercise
  2. Nutrition
  3. Stress

We'll discuss nutrition and stress later, but for now, it's important to know they play a role in your MAF training.

The goal of MAF training is to strengthen your aerobic base so you can run faster at a lower heart rate. This is done by performing all of your training at or below your MAF heart rate ceiling. By doing this, you're delaying when your body needs to tap into your anaerobic system. 

Any run over half a mile will tap into both aerobic and anaerobic energy. The longer the run, the more your body will depend on your aerobic system. Which is why using MAF training can be beneficial for marathon runners.

Our body uses two systems for energy: The Aerobic System (with oxygen) and the Anaerobic System (without oxygen).

The Aerobic System powers our muscles by using oxygen to convert fat to energy. A well developed aerobic system will allow you to run a long time.

The Anaerobic System kicks in when oxygen is being depleted faster than its being taken in. To create the necessary energy, our muscles begin to break down glucose. Your body will tire quickly and you won't be able to run long distances using the anaerobic system.

Research has shown that the majority (about 80%) of your running should be done in the aerobic zone. This is the most efficient and safest method of training.

But developing a strong aerobic base is also important for shorter races since you'll be able to maintain a comfort zone (opposed to the critical zone) for longer periods of time.

Beyond running faster at a lower heart rate, MAF training will also deliver these benefits:

Measuring Your Heart Rate

With MAF training you're going to need to measure your heart rate on a regular basis during your training. To do this, it's a good idea to purchase a quality heart rate monitor designed for exercise. Some use a strap that goes around your chest to capture your heart rate. The data is then transmitted to an app or other device such as a watch that displays the number. 

As technology has improved, there are many watches capable of capturing your heart rate without the use of a chest strap. The important thing is to find a heart rate monitor you're comfortable wearing during your training, and it provides accurate information.

Woman running in the park

How to Determine your MAF Heart Rate

In order to use the MAF method of training you'll need to know your MAF heart rate. Once you determine your MAF heart rate it's critical to use it for all of your training runs. You'll no longer need to focus on speed or pace, only your heart rate and the amount of time on your feet.

The 180 Formula

To calculate your MAF heart rate you'll subtract your age from 180. So, if you're 30 years old, your MAF heart rate will be 150 (180 - 30 = 150).

With that said, there are several lifestyle factors to consider which will either increase or lower your MAF heart rate. For instance, if you're recovering from a major illness, you'll subtract 10. So a 30 year old with a MAF heart rate of 150 would then subtract 10. In this example, the MAF heart rate would be reduced to 140 (180 - 30 = 150 - 10 = 140).

Your training zone (in this example) is 130 to 140. 

When your heart rate hits 130 (10 beats below your MAF heart rate) you'll want to increase the intensity of your run. When it reaches 140, you'll want to slow down.

All of your training will be done within this heart rate training zone. 

Calculating Your MAF Heart Rate

Subtract your age from 180, then modify from one of the categories below:

  1. 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.
  2. 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 over fat, 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.
  3. If you have been training consistently (at least four times weekly) for up to two years without any of the problems mentioned in 1) or 2), no modification is necessary (use 180 minus age as your MAF HR).
  4. 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 (4) 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.

Source: philmaffetone.com

Once you determine your MAF Heart Rate, you'll do all your training at or below this heart rate for a minimum of 3 months. The goal is to train your body to increase its need to burn body fat for energy, which will not only help you build a strong aerobic base, but also become a better fat burning athlete.

When beginning a MAF training program, nearly all runners need to decrease their pace in order to stay at or below their MAF Heart Rate. It's not uncommon to need to jog or even walk to make this happen.

Runner on treadmill taking MAF Test

MAF Test: Tracking Your Progress

As with any training, you'll want to track your progress, and in this case your aerobic development. This can be done using the MAF Test. It's simply a test that you'll do (typically every month) where you run a fixed distance or time at your target MAF heart rate.

The results of MAF Tests are helpful because they'll alert you if you're headed in the wrong direction. Think of the results as a tap on your shoulder to point out issues in your training. You'll be able to do some troubleshooting and adjust your training. 

If your training is generating too much anaerobic exercise, or there's something else negatively impacting your aerobic system, such as a poor diet or stress, then you'll want to make changes. By improving your future MAF results you'll not only see aerobic improvement, but you could also prevent future injuries.

Performing the MAF Test

Ideally, you'll want to do a MAF test once a month to measure your aerobic progress. You'll first need to decide if you want to do a distance-based test or a time-based test. Whichever you choose, you'll want to use for all future tests.

Distance-Based Test - Choose a distance to cover during the test. Such as run 5 miles at your MAF heart rate. You're looking for an improved pace. 

Time-Based Test - Decide how long you'll run during the test and measure how much distance you cover at your MAF heart rate. Most runners typically run 60 minutes during the test. On a time-based test you're looking to cover more distance, but keep in mind you'll be covering more distance because your pace improved.

Steps to the Test

  1. Warm-up for 15 to 20 minutes (be at your MAF heart rate when you start the test)
  2. Begin running on a track or treadmill for your designated time (60 minutes) or distance (5 miles)
  3. Maintain your MAF heart rate as close as possible for the duration of your test
  4. Record your split times. Most training watches will do this for you
  5. Once finished, analyze your results and compare to previous tests

If you're showing aerobic progress, you should notice that you're able to run faster at the same heart rate. Keep in mind, you're looking for progression over multiple data points, and results take time.

Don't be alarmed if you notice your pace slow during your later splits. This is not uncommon and your body is simply responding to the fatigue. As you become aerobically fit, your pace will become more consistent.

Although somethings may be out of your control, try to keep the variables in your test at a minimum. For example, running on a track will provide the same flat surface for each test. In fact, if you have access to a treadmill, this is the ideal way to conduct your test.

Watch the Video to See Actual Results

Runner strapping on heart rate monitor preparing for MAF Test

7 Reasons You're Not Progressing with MAF Training

Athletes who do MAF low heart rate training typically find they are stronger and healthier. They also burn more body fat, increase their energy and brain function, and have a lower risk of injury. In addition, they have a higher level of endurance and physical fitness.

But what if you're doing MAF training, but you're not progressing? Here are the most common reasons you may not be seeing results:

Not Sticking to Your MAF Heart Rate

If your MAF heart rate is not set correctly, or you're consistently going over it when training, you're not going to be getting the desired results.

Incorrect MAF HR

You may have calculated your number incorrectly and during your training you're sticking to a HR that is actually higher than it should be. In other words, you think you're in the right zone, but you're actually not.

This is an easy fix and you can simply recalculate your MAF HR by using the 180 formula. Be sure to adjust the number accordingly with the modifiers.

Going Above MAF HR

If your training zone is 130 to 140, you should be slowing down your pace when you reach 140 beats per minute. When training with a heart rate watch, it's a good idea to set an alarm to alert you when your heart rate hits 140.

When the alarm goes off, immediately reduce your pace.

Many runners who start training with MAF become frustrated that they need to constantly slow down or even walk to maintain their heart rate within the desired range. This will pass as you become more aerobically fit, you simply need to trust the process.

Women doing agility training

Over Training

Over training is a common reason athletes don't see results with MAF training. The "no pain, no gain" mentality leads to a belief system that we won't see results unless we push our bodies to exhaustion.

If you've been doing a lot of high-intensity training, its possible your body has entered a physiological state of fight-or-flight. This reaction occurs when your body perceives a threat to survival. This is a stressed state that never allows you to fully relax. Although you may notice better times/distances covered on your runs, your body is operating at an unhealthy performance level.

In order to move your body from survival mode, where it's responding like it's in the fight of its life, you need to slow your training intensity. This will allow your body to return to a more natural state.

If this is the reason you're not seeing results with MAF training, be patient with yourself as it could take more time than you think to repair the damage done. Be consistent and keep a positive mindset as you go through the process.

Also, pay close attention to getting enough sleep, as well as your rest and recovery patterns. These are all important elements that'll improve your training and reduce your stress.

Recovery is critical when it comes to MAF training. Since you'll likely be running slower than you were before, it's easy to add additional training days and skip recovery days, or increase distance too fast. This is a mistake and can lead to over training.

A good rule of thumb when building your training volume is to add no more than 10% in volume a week. And take a step-back week every fourth week by reducing your training volume by at least 30%

Poor Fat Burning

If your nutrition isn't great and/or you've been overtraining, your body will need some time to repair the damage. With time, you'll see improvement, but your body will need to "learn" to efficiently burn body fat.

Every workout you do will place stress on your body, and many runners do strength training and cross training in addition to their training runs. If you have poor nutrition, or you've been over training, you may want to consider lowering the intensity while MAF training. In fact, during the first few months, you may want to cut these "extra" workouts out entirely.

Poor Nutrition

Since your primary goal with MAF training is to improve your aerobic function, which results in improving your fat burning abilities, consuming a well balanced diet is crucial to your results.

Simply put, regardless of how well you train, if you're eating a lot of refined sugars and processed food your results will be negatively impacted. You'll be able to burn more body fat if you eat healthy, unprocessed meals, which in turn will help improve your aerobic system.

You can experiment with how your body responds best to your balance of macro nutrients and times of eating. Just don't do anything crazy like cutting carbs out or short intermitted fasting windows. Try to eat a balanced diet with unprocessed carbohydrates, proteins, and fats. Typically, most athletes do best when they eat at least 3 meals a day with 1 to 2 snacks.

A runners diet can be every bit as important as your training sessions.

Woman on treadmill taking a MAF Test

Inadequate Warm-up

Warming-up before a workout is not only important for your muscles and injury prevention, it can also play a role in your heart rate. When your body is not properly warmed-up, your muscles will contract and your heart rate will increase quicker than it should. This will flood your legs with blood and place unnecessary stress on your body.

Allow your body to warm-up for at least 15-minutes. One method is to start with a 5-minute walk, then a slow jog where you gradually increase the pace until you hit your MAF heart rate.

A slow warm-up will allow the blood to move from your internal organs and transfer to your muscles. 

If you haven't been doing a gradual, slow warm-up, and you have a tendency to jump into running too fast too soon, then you'll likely see a noticeable difference in your MAF test results.

Muscle Imbalance

In order to bend your elbow, the bicep contracts while the tricep relaxes. Then the opposite occurs to straighten your arm. The bicep and tricep are called opposing muscle groups. 

The hamstrings and quadriceps work in the same way to extend our knees, as do other major muscle groups.

However, when there is a muscle imbalance, one of the muscle groups is a different size or strength than the opposing muscles. When this happens, the stronger muscle can "overpower" the weaker muscle group. This can result in poor posture, form, and ultimately injuries.


Stress is a part of life, but if you are experiencing high levels of stress it could impact your MAF results by blocking your aerobic development as well as reduce your fat burning.

If you're a big coffee drinker or consume your caffeine in other ways, you may want to consider reducing your intake. Caffeine has a tendency to increase anxiety as well as your heart rate.

Also, pay attention to your sleep patterns and that you're getting enough sleep. It shouldn't come as a surprise a high percentage of people are sleep deprived. If you enjoy geeking out, there's a variety of different products on the market to help you analyze your sleep. Our favorite is the Ōura Ring, you can wear it only at night or 24 hours a day and download an amazing amount of data.

You may also want to consider downloading the Calm App. This app has a variety of guided meditations, sleep stories, and master classes to help you lower your stress. They're always adding new material and it's well worth the small annual fee.

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