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Zone 2 training - The Basics
The benefits of slowing down
👋Hello, my friend - I've got 2 things to share today:
A 101 explainer on Zone 2 heart rate training - a topic I’ve recently become obsessed with
The best resources I've found on this subject
Let’s do it!
The 411 on Zone 2
I thought I was done running.
Ten years ago, I found myself on the chiropractor's table twice a week. I was searching for relief from chronic sciatica - a radiating pain going up and down my left arm and leg.
The culprit? Running. Too much pounding. I had herniated discs they told me. Compressed vertebrae. I even had a couple of cortisol shots for relief. Not fun.
So I gave up running. For good (I thought).
It wasn't THAT big of a deal. I was never all that serious about it in the first place. I had run some cross country and track in high school but was never very skilled at it. I'd run some races as an adult - mostly 10k's - and had even managed to eek out a half marathon back in 2003. That was pretty much the height of my running career.
But recently, through a culmination of events, I realized that my cardiovascular health was not where I wanted or needed it to be. My HRV was low. My resting heart rate was not particularly impressive. And according to my Apple Health app, my VO2 max was below average.
“What gives?” I thought. I work out daily. I log multiple Peloton rides every week. I lift weights. I’m active. I thought I was supposedly in good shape!
But the data doesn’t lie. So, I decided that I needed to face all of these facts head-on.
Around the same time, I'd been reading more and more about heart rate zone training.
The concept is not a new one. It's been around in various iterations for decades. But it seems to be catching fire recently as more and more people become aware of its benefits. And I thought “this might be exactly what I need.” So I dove in. And below is what I’ve learned - so far.
Heart rate zones - the basics
There are five heart rate zones. You're probably in Zone 1 right now reading this. That's where we spend most of our time. At the other end of the spectrum is Zone 5, which is all-out, as hard as you can go, intense exercise.
There are enough different methods for calculating heart rate zones (see here) to make your head spin. The most commonly known way to do it is by subtracting your current age from 220 to get your max heart rate. And then finding your zones based on the percentages below. However... this age-based method has been shown to have significant flaws (and there's not even agreement on the %'s listed below).
Zone 1: 50 - 60% of MHR.
Zone 2: 60 - 70% of MHR.
Zone 3: 70 - 80% of MHR.
Zone 4: 80 - 90% of MHR.
Zone 5: 90 - 100% of of MHR.
More on how I’m tracking it in a minute…
However you measure it, there is something special about Zone 2.
Zone 2 is arguably the zone where you can drive the most positive changes for your body over a sustained period, potentially including:
A lower resting heart rate
Improved metabolic functioning
Decreased blood pressure
Increased ability to run/cycle/exercise for longer
Even greater longevity
Zone 2 training - also known as base or aerobic training - involves doing (typically) longer workouts with less intensity. For most people, including myself, Zone 2 equates to a very slow running pace (with periods of walking) that you can sustain for a long time (think 45+ minutes) all while comfortably having a conversation.
This type of training has been studied extensively in the world's most elite athletes - from runners, to cyclists and beyond.
Time and time again, the conclusion has been as follows:
The athletes who modify their training schedules to spend ~80% of their training time in Zone 2 tend to outperform those who spend the bulk of their time at higher intensities.
This is counterintuitive given how easy it feels and the "no pain, no gain" fitness culture that has proliferated for most of our lives — but the results have been so astonishing that Zone 2 training has become the standard for many of the world's most elite athletes.
Despite these athletes having figured this out some time ago, weekend warriors like you and me mostly haven't caught on yet. And that’s crazy because the benefits to everything from metabolic health to longevity can potentially be immense for us normal folk.
Studies show that amateur runners tend to spend 60%+ of their training time at moderate intensity (that’s Zone 3+). In other words, we're actually going too fast. We are overtraining, when what we really need is to go slower and longer.
Does this mean we should NEVER go fast? No, based on numerous studies in a variety of scenarios, we should aim for high intensity workouts for ~20% of our cardio sessions. But high intensity means high intensity. It means getting yourself breathless. It means testing that max heart rate. It means leaving it all out there. Are you doing THAT 20% of the time you run or cycle? I’m not sure I am.
While many of us *think* we are doing a great job keeping ourselves in good cardiovascular shape, almost all of us are spending the bulk of our cardio time in the so-called "garbage zone."
We’re going too fast and too hard on low intensity days (ideally 80% of cardio workouts) and too slow or not hard enough on high intensity days (ideally 20%) of cardio workouts). We’re missing out on both ends.
As I look back at my cardio workouts over the past several years, they almost all fall in the garbage zone. No wonder my metrics look bad. I haven’t ever take the time to build a solid base.
So what can this actually look like in practice?
Based on studies referenced by Inigo San Millan and Peter Attia (see links at the bottom), to achieve the max benefits of Zone 2 training, athletes must workout in Zone 2 for at least ~45 minutes at least 3 times per week.
If you have 4 cardio workouts per week, this means that 3 of them should be these longer, slower sessions. And one would be a shorter, leave everything you've got out there type of workout.
What I’m Doing
I've been working on integrating this into my own workout schedule recently and here's what a sample week looks like:
For those who are interested, I am currently using my Apple Watch and the Apple Workout and Fitness apps to track my own zones. Purists will argue that wrist-based heart monitors are garbage. As a (ahem) non-elite athlete, I've found my Series 8 watch to be pretty damn good for what it’s worth.
Anyhow, Apple, of course, uses a different methodology than most others called the Heart Rate Reserve Method to calculate zones.
Instead relying on age alone, this method accounts for the difference between your actual Max Heart Rate and Resting Heart Rate to calculate your zones.
Here's the equation to determine the upper bound of your Zone 2:
0.7*(Max HR - Resting HR) + Resting HR
The nice thing about the Apple Watch is that it automatically tracks and recalibrates Max HR and Resting HR on a monthly basis and then dynamically adjusts your zones for you.
For some purists, this may not cut it. For this weekend warrior, I appreciate that it does the work for me.
My current HR zones are below (they are a work in progress!):
If you have an Apple Watch running the latest software (and you have your age entered into the Health app) you can find this as follows:
Open Apple Watch app on phone → Workout → Heart Rate Zones.
A few final tips
If you’re intrigued by all of this and want to try it out, expect to run SLOW. I’ve been going for nearly a month. I’m averaging a 14-minute/mile pace to keep my HR in Zone 2 for 45 mins. This is good and bad. On the bad side, some might be embarrassed to run so slow. And it can be frustrating to have to walk (especially on hills) to keep your HR in Zone 2. On the good side, it’s not hard. It’s even… dare I say.. enjoyable? Plus, the whole idea is that as your aerobic fitness improves, you’ll be able to go faster and faster and stay in Zone 2. This is my plan but I’m expecting it to take several months before I start to really see progress.
Don’t get injured! I went to a running store and had them look at my gait, how my feet strike the ground, etc., to make sure I had the proper shoes. I recommend doing that if you can. Also, STRETCH! Some quick dynamic stretches before a run followed by longer static stretches afterward seem to be best practice.
If you’re using an Apple Watch, you can set it up in the Workout app so that it’ll buzz you when you’re out of Zone 2. Next time you see me (slowly) running down the street, you’ll know what all that buzz is about. Zing!
I’ve been bingeing everything I can recently on Zone 2 training. Below are the best resources I’ve found to-date:
(I'll warn you that both of these get pretty scientific & technical.)
80/20 Running by Matt Fitzgerald - I’ve been listening to this (on long, slow runs) and I’m really enjoying it. It’s packed with both theory and real-world examples of why this way of training makes sense.
Zone 2 Heart Rate Training For Longevity and Performance (Dr. Howard J. Luks)
Complete Guide to Apple Watch Heart Rate Zones (MyHealthyApple)
Which Method is Best to Find My Training Heart Rate? (Beginner Triathlete)
Thanks for reading. I’m still a Zone 2 newbie so if you think I’ve got something wrong here (or want to suggest additional resources), hit me up in the comments section of this article on Substack or find me on Twitter @gregorycampion.
See you in two weeks… when I’ve got an AWESOME podcast guest who you might recognize.
In case you missed my recent conversation with Dickie Bush… we got into Zone 2 a bit. I’m going to be discussing this more with some upcoming guests on the podcast.