Dear Mark: Maximum Aerobic Function (MAF) Training

maximum aerobic functionFor today’s edition of Dear Mark, I’m going to be answering questions about Maximum Aerobic Function, or MAF. If this is your first time hearing the term, MAF refers to a method of endurance training that maximizes the function of your fat-burning aerobic system. I’ve come down hard on conventional or popular modes of endurance training in the past for being too stressful and reliant on sugar. MAF training is the opposite: low stress and reliance on body fat.

Let’s dive right in to the questions:

What is MAF training?

MAF trains your aerobic fat-burning system to be more efficient and produce greater output at the same “intensity.” It means slowing the hell down to go faster. It means the slower you go, the more fat you’re burning and the better your mitochondria are getting at utilizing fat for energy. It means training up to but not over your maximum aerobic heart rate.

MAF was coined by Phil Maffetone, who came up with an ingenious way to calculate your max aerobic heart rate: subtracting your age from 180. 180 minus your age gives you the heart rate at which you’re burning the maximum amount of fat and minimum amount of sugar.

Say you’re 30 years old. 180 minus 30 is 150. To burn the most fat possible, you maintain a heart rate equal to or lower than 150 BPM. Now, and here’s the trick: It doesn’t sound like much. It doesn’t feel like much. It probably feels way too easy. But bear with me. It works. This is where the magic happens, where you accumulate easy volume, where the “base” is built, where you begin building more fat-burning mitochondria.

The hard truth is that if jogging spikes your heart rate past your aerobic max, you’re not very good at burning fat during exercise. Even if you don’t “mind” pushing that heart rate up. Even if you “feel fine” jogging at 153 bpm. 180 minus age is where you have to be to improve fat burning. That might look like jogging, or walking, or walking uphill, or running pretty briskly, depending on where you’re starting. It’s all relative to your aerobic fitness.

It takes patience to stay at the aerobic zone, but over time, if you’re consistent, you’ll notice that you can handle a higher and higher workload at that same “easy” MAF heart rate. You’ll be going faster while still burning mostly fat—and it’ll still feel easy.

What are the benefits of cardio using MAF training?

In some parts, I’m known as the anti-cardio guy. I coined the phrase “chronic cardio,” and the entire reason I got into this Primal business is that decades of elite endurance training—marathons and triathlons—wrecked my body and drove me to develop and pursue a different, more sustainable path to health and fitness.

But I’m not anti-cardio. In fact, moving frequently at a slow pace in all its incarnations forms the foundation of my Primal Blueprint Fitness philosophy. And MAF is just about the best way to do it.

When you build your aerobic base, you don’t just get better at running (or cycling, or rowing, or swimming, or whatever it is that you’re doing). There are more benefits that aren’t as overtly noticeable: