October 11, 2021

A Simple Explanation of MAF Heart Rate Training (and why I love it!)

I just got back from an evening run, and I just have to write this down so I remember it: the circumstances in THIS RUN are exactly the reason I fell in love with MAF training back in 2015.

I'm going to back up and bit and just explain what MAF is and its significance to me (as well as to my running coach style). If you've been reading my blog for a long time, then you can skip over all this...

MAF stands for "maximum aerobic function" (don't worry, I'm not going to get technical about all this, even though I am a total nerd for it; I'm going to keep it very simple here). It was developed by Dr. Phil Maffetone ('MAF' and 'Maffetone' are purely coincidental). Here is how his logic works:

Everybody has a MAF heart rate. There is a formula on his website which takes into several factors, but for the general population--as well as the way I use it--you subtract your age from 180 to get your MAF heart rate. I'm 39 years old, so my MAF rate is 180-39=141. The "golden rule" of MAF training is that you don't exceed your MAF heart rate while exercising.

(Note: Your MAF rate is a single number, but since it's nearly impossible to consistently train at that solid number, Dr. Maffetone says to create a range of 10 beats per minute below your MAF rate, with your MAF rate being at the top of the range. Since my MAF rate is 141, my MAF range would be 131-141 beats per minute. )

For almost everyone, this means exercising considerably easier/slower. For runners, it can feel painfully slow and ridiculous. There is a reason for training at this pace, though, otherwise people wouldn't do it.

To keep things simple and easy to understand, I won't get into the physiology of it, but according to Dr. Maffetone, when you exercise at your MAF heart rate, your body gets more efficient and when you eventually add more stress (running faster, cycling harder, whatever your exercise is), your heart won't have to work harder to keep up. You will be putting in the same amount of EFFORT (as evidenced by your heart rate), but you will improve your fitness level.

I'll use running as an example, since it's my "thing": Let's say I run a 5K race at 10:00 minutes per mile (running as hard as I can for that race). Then I start MAF training: I do ALL of my training runs at or a little below my MAF heart rate--in this case, 141 beats per minute. While it feels like I'm not working hard, I am actually making my body more efficient.

Over a period of several months (more or less--it varies greatly), I might need to start running a little bit faster in order to get my heart rate up to 141 bpm. It will still feel just as easy--I'm still stressing my heart the same as before--but I'll be able to do more/work harder in order to get my heart rate to that number.

Then, because my body has become much more efficient over, say, six months, I might run another 5K race at the same effort as the first one (pretty much as fast as I can) and my pace might be 8:00 minutes per mile.

To put it super simply, when MAF training, you're not working HARDER in order to become more fit; your body is just becoming more efficient at the same effort.

I will use myself as a testament that it really works:

In 2015, my pace had gotten much slower than I used to run. My 10K pace was about 11:00 minutes per mile (just two years prior, I had run just under an 8:00/mile pace in the 10K). My training had never involved my heart rate--I used my pace to gauge my fitness and my training. I did my "easy" runs at a heart rate of about 20 beats per minute OVER my MAF rate!

After getting over a stress fracture, I finally decided to try something I'd never done before: running at a truly EASY pace, by the very definition.

I read a book called '80/20 Running' by Matt Fitzgerald (Amazon affiliate link) that had a huge impact on my training. I combined what I'd read about MAF training with 80/20 running (and my knowledge as a running coach) to produce my own training plan. The biggest change in my training was that I began running MUCH slower than I was used to. I did at least 80% of my training at my MAF heart rate--and that translated to a pace of 11:00-12:00/mile.

Per the 80/20 method, I also did a small amount of speed work (no more than 20% of my TIME spent running per week was done at a heart rate higher than my MAF rate). Here is an explanation I wrote about how I combined the two methods to train.

I found that I was getting faster on the days that I did my speed work and that I was able to run slightly faster while maintaining my MAF heart rate during training. There wasn't a huge difference in the training pace, but I could see progress.

I was training for a goal 10K in April 2016--which was about five months after I started running at my MAF pace. I ended up running my goal 10K in 49:03 (a 7:54 per mile pace!).

Running my easy runs EASY was the best change I could have made in my training. I have no doubt that my combination training (I really should name it something--I made the training method by combining 80/20 and MAF in my own way.)

Anyway, why am I writing about all this again now? (Because you're hypomanic, Katie!) (Just kidding.) (But not really.)

Because my run this evening brought back all the good feels from my MAF training and it makes me want to do it again.

When I first ran at a truly easy pace (my MAF heart rate), I just let go of any and all expectations of my pace (that's very hard to do as a runner--we always want to go faster.) To be successful at this training, and to actually enjoy this training, you have to set your pride aside and trust the process. Someone is giving you ORDERS to go slowly, so enjoy it!

Today, I decided to run at my MAF heart rate range (131-141 bpm) and just see where my pace was when I ran at that heart rate. At first, my thoughts were focused on how slow I was and it's going to appear to others that I am losing fitness and all those thoughts that we need to get over in order to train properly. Once I embraced the slower pace, a big change came over me. I felt wonderful!

I didn't feel out of breath and I stopped focusing on how much longer until the run is over; I started to think that maybe I'd run farther than planned. I had planned to go just two miles and I procrastinated all day long because I didn't want to do it. Once my mindset switched over to that MAF feeling, I felt like I could run for hours (which is how you SHOULD feel when you are running at a truly easy pace). I tacked on an extra mile. When I stopped my Garmin in front of my house, I didn't have to catch my breath. I felt like I'd just gone for an easy walk. I actually felt really excited!

And maybe it's just because I'm hypomanic, but I started thinking that I want to train at my MAF rate again. Not only that, I want to write a new training plan--a lower mileage plan for beginners to MAF training. I am not interested in building up mileage--I only want to run enough to stay fit, at least for the near future--so I want to keep my mileage relatively low. I want to do my own method of combining 80/20 running with MAF.

I have written a couple of plans (that you can find here--named "Your Best 5K" and "Your Best 10K") for 5K and 10K training in this way--those plans were the most challenging plans I've ever written because I had to make all of the math work! However, even the 5K plan has more mileage than I want to run.

I don't want to train for a race or to hit a particular goal. I just want to use the training method because I enjoy it. So, I'm going to work on writing up a training plan for that purpose. (Let's hope it's not just my hypomania talking--this is a textbook example of something like that!)

Since I usually write about my running on Thursdays, I will try to write more about it then. Hopefully I can get the plan done this week!

Note: Something that people always ask about when I write about MAF training is that they can't run and stay under their MAF heart rate. The only way they can stay at that heart rate is to walk (or at least take walking breaks). Dr. Maffetone would say to do whatever it takes to stay in your zone. This really sucks for people who want to run! (And this is the reason that I wasn't doing MAF training as I got back into running--I just wanted to run for the feel of running.)

The training will work if you follow it as Dr. Maffetone states, if you're willing. You will eventually be able to run and maintain your MAF heart rate; it just takes patience. I think one of the biggest factors as to how fast that works is just how much training you're doing.

To a certain extent, the more you are training at your MAF rate, the faster you're going to see progress. Doing 30 minutes 3 times a week is likely to take a lot longer than 60 minutes 5 days a week. (Keep in mind that the training is EASY, so doing a 60 minute run/walk/other exercise at MAF heart rate isn't going to exhaust or overtrain you.)

If there is only one post you read about proper training, let it be this one: The Importance of the Easy Run!

To read all of the details about the MAF method (it goes into WAY more than just the heart rate training) you can find it on his website.


  1. Thank you!! I had many many many questions as you were posting your zones. This helps me understand. I'm a HUGE MAF180 fan. It's made running so much more fun and, hey! No injuries lately. Oops. Did I say that out loud. Hope I didn't jinx myself. But it's good stuff. I love that you wrote this all down, hypomanic or not.

  2. I feel the same way about running. I have slow read that this type of running burns more fat. I am trying to lose the pandemic pounds right now. I have a eau you go but running is helping.

  3. I'm so glad you posted this! I've been meaning to get back into running, but haven't yet. The other day, a friend asked me to walk a hill with her, and it was so much harder than I thought it would be, but I also loved how I felt for the rest of the day. I'm doing it on my own right now so that I won't slow her down as much next time. I was wondering today what would help me get faster, and it's probably this method! I realize it wouldn't be overnight, but it'd be fun to track! Now I'm on the hunt for a cheap(ish) heart monitor.

  4. I recently did your 1/2 marathon plan and loved it. My 5th one, and I had a 4 minute PR! Even better, I really grew to love running for both stress relief and exercise. I got the 80/20 Matt Fitzgerald book based on your recommendation and love it. Currently training for a 10k based on his plan. Thank you for leading me to it!

  5. I think a training plan for MAF beginners is a great idea! I'm struggling to embrace the MAF method. I live in a suburb of Denver, so altitude is a factor for my HR. Also, I live in a hilly neighborhood, so again, my HR climbs quickly. Basically, every time I try MAF training, I can barely run, and mostly only power walk. I get so discouraged. My MAF zone is 128-138, and it doesn't take much for me to get up there. I think a beginner plan would help me stay the course. I'm prone to injury, and just healed from a stress fracture myself, so I know that I'm putting too much stress on my body.

  6. Hi Katie! How do you keep track of your heart rate range while running without staring at your wrist? Is there a way to set up the range on your heart rate monitor and have it beep when you go higher or lower? Sorry if this is a dumb question but I’ve never run with a heart rate monitor going, I’ve just used my watch for mileage. Thanks!

    1. My Garmin has the feature where you can set it to beep when you go over the heart rate that you choose. However, I don't really recommend that, especially in the beginning. The beeping will cause your nerves to spike your heart rate! Haha. And the chances are, when you first start heart rate training, you'll find yourself at too high of a heart rate very frequently until you get used to what it feels like. Now, I glance at my watch every few minutes or so. If it's on the low end of my range, I try to stick with that current pace and I don't have to look at it much. If it's on the high end, or over my target rate, then I slow way down and glance at it every 30 seconds or so until it's quite a bit lower. It takes some getting used to, but once you get in tune with your body, you can get a pretty good feel for your target rate without looking!


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