I hate running. I’ve never been shy about saying that. When I was in the Air Force, I dreaded most PT sessions because they always devolved into some variation of running. When it came to the annual physical fitness tests, I was perfectly happy with the strength components, but I despised the run.
Can you relate?
Some people just seem to have a natural gift for it. I’m not one of them, and I’ve had to work hard to get my run times down to the okay-ish numbers they are. A lot of the guys I served with ran 1.5 miles in 8:45 like it was no big deal. My best time ever was 10:40, and I was smoked.
But this post isn’t about my run times. It’s about aerobic endurance and some of the things I’ve learned in my pursuit of run times.
Enter Dr. Phil Maffetone
I first came across the work of Phil Maffetone while reading a book by primal health guru Mark Sisson. If you’ve never heard of him, that’s OK.
Mark Sisson is a life-long elite endurance athlete, supplement designer, and one of the thought leaders in the primal/paleo/keto lifestyle spheres. I’ve followed his writings for a long time and it just works for me. But I’m not here to preach that to you.
In the book, Mark breaks down Dr. Maffetone’s idea to something pretty simple. Most people know about the max heart rate zone formulas printed all over gym cardio equipment. Forget that.
Here’s the quick and dirty version, I’ll dig into the deeper science in a minute.
According to the Maffetone Method, subtract your age from 180 and you arrive at your max heart rate. So, for someone 30 years old, it would be 150.
For our 30 year old athlete, that means 145.
This is the heart rate you shall not exceed during routine cardio training. Notice that I said cardio training, not anaerobic training, work capacity days, or anything like that.
Let’s talk about this.
The Dreaded “Dead Zone”
If you’ve done any reading at all about fitness, and particularly endurance, you’ve probably come across aerobic and anaerobic function.
- Aerobic: Lower intensity exercise that draws energy from fat stores and saves the body’s sugar stores for later
- Anaerobic: Higher intensity exercise that primarily draws energy from the body’s sugar stores
The name for each of these modes stems from biology and refers to the presence or absence of oxygen during metabolism. In exercise terms, it’s a distinction between when your body has an adequate supply of oxygen in order to metabolize fat (aerobic). If the work demand exceeded the heart and lungs’ ability to supply oxygen then metabolism switches to sugar burning mode (anaerobic).
Traditionally, heart rate is a good proxy for estimating the intensity of exercise. As the intensity went up, so did the demand for oxygen. The body responds by increasing the heart rate and circulating more blood through the lungs (which also get an increase in respiratory rate) and muscles.
Dr. Maffetone put together a chart that shows a rough estimate for heart rate, respiratory load, and metabolism sources. The respiratory load in the chart has the designation RER, which stands for Respiratory Exchange Ratio. This chart is focused on an already aerobically fit athlete, so your mileage may vary dramatically. But It illustrates a point well.
The harder your level of exertion, the more you’re relying on your body’s carbohydrate stores to provide energy. If you’re like most average humans, you have way more fat stores for energy than carbohydrate.
In order to teach your body to efficiently metabolize fat for fuel, you have to train in the aerobic zone. That means plenty of available oxygen and relatively low intensity.
If you want to train for high exertion and sprint capacity, then you train in the high effort zones and teach your body to efficiently use carbohydrate stores.
What Mark Sisson points out is that your body is not really good at doing both at the same time. It’s kind of an either/or proposition. That’s not to say that it can’t do both, but you’re not receiving much training benefit by spending your time in this middle ground.
This is the “dead zone.”
And, unfortunately, this is where most gym goes slaving away on treadmills or jogging around your neighborhood are hanging out. If you want to really train your body to efficiently use fat stores for energy, which allows you to keep up your performance for long periods of time without “carbing up,” then you need to train at a lower heart rate.
The Maffetone Method of Aerobic Base Training
Most people, including me, approach “cardio” the same way. We pick a distance, say 2 or 3 miles, and time how long it takes us to run it. If our time gets better from week to week, then we say that we’re getting better at cardio.
But here’s the thing, I wear a heart rate monitor when I run and I know my heart rate is well into the anaerobic zone by the end of it. I’m not really training cardio anything at that point.
So let’s reverse the formula.
The standard test for the Maffetone method is not how long it takes you to run X distance, but how far you go after moving for X amount of time while keeping your heart rate below your max.
So for my average cardio workout, which is rowing, that means I set a timer for 30 minutes and go. I check to make sure my heart rate never exceeds 145 BPM. At the end of 30 minutes, I record the distance.
As I keep training, that distance gets longer.
This is what it means to improve your aerobic base. You are improving your body’s ability to sustain low to
Now here’s the hard part: this process is slow. When starting out, you are going to feel frustrated by how slow you’re moving relative to what cardio used to feel like. It’s very common for someone doing this low heart rate training to have to stop and walk a lot during a run in order to stay below their max heart rate.
It’s ok. Keep showing up and you will improve over time.
I’m not going to dive very deep into metabolism. I’ve done a ton of reading on the subject over the years, so it’s a topic worthy of its own post. But I do want to point out that our society is a little broke in this regard.
Plentiful carbohydrates aren’t the natural state of things. The traditional human diet throughout history included protein from animals, fat from animals and plant sources, and carbohydrates from plants. The thing is, it was very difficult to eat enough plant-based carbohydrates to sustain the body for long periods. There was no supermarket to load up piles of produce and supplements. And, for much of the year, all the plants were dead.
But I digress. I’m not saying this to be preachy, but to highlight that our society is off track. Our bodies will not metabolize fat if carbohydrates are available.
In fact, a high level of glucose in the blood is toxic. If excess glucose (sugar) is present, our bodies will do everything they can to use it or store it. Once dealt with, we pivot back to metabolizing fat.
Here’s the trouble, though, our diets consist of so much sugar that we never get to pivot back to fats. By the time we dealt with the bagel from breakfast, we’re chomping down a sandwich at lunch. When we process that, it’s time for pasta and beer at dinner.
That pattern means most of us suck at metabolizing fat.
So what does all of that have to do with other benefits of the Maffetone Method?
Aside from being able to sustain a workout longer, I’ve noticed a lot of other little changes in my day-to-day.
Firstly, my energy levels are much more stable, without large spikes or lulls. My metabolism is flexible and better able to switch back and forth.
Is my diet perfect? No. I know I have some work to do there, but don’t appear to have anywhere near the issues a lot of my coworkers have with not eating every
I find that I can wake up at 5 AM, go work out, come home, shower, get dressed, and get some writing done all before I start to feel hungry. It’s almost three hours between when I wake up and when I eat, with a lot of activity in the meantime. And that’s on top of not eating since dinner the night before, which is typically around 6 to 6:30 PM.
That’s routinely fasting for 14 hours, with
Another benefit I’ve noticed is decreased recovery time from my workouts. I’m better able to come back to a baseline and stick with a workout for longer. My overall high-intensity work capacity is still something I’m pushing, but the “grind” stuff is definitely easier to bounce back from.
Give it a try for a bit, what do you have to lose?
So all of that to say that there’s another way of approaching your cardio routine that you might not know about.
Subtract your age from 180 and call that your maximum aerobic heart rate. When you have a dedicated “cardio” session, never exceed that number. Pick a time to work, 20 minutes minimum, and slowly see how your distance improves.
I want to point out that the Maffetone Method is actually an overall lifestyle of health, fitness, and nutrition. I’m just focusing on the aerobic training part of it all. But definitely check out more of his work if you’re interested.
I realize that aerobic training like this isn’t as exciting as a grueling work capacity or lifting session. But, in the end, being able to sustain your energy during low to
This also works great for rucking, by the way.