Heart Rate Zones: How to Find Yours and Get Them Right
- Ben Barwick
- 4 days ago
- 8 min read
In the last post I made the case for why you'd want to train to heart rate — that pace is contaminated by the weather, the hills, your sleep and a dozen other things, and heart rate gives you an honest read on how hard you're actually working. If you've not read that one, start there, because this post picks up where it left off.
Because knowing the why is one thing. Actually getting it right is another. And here's the honest truth: heart rate training is only as good as the numbers you feed it. Get the zones right and it's one of the most useful tools you can put in your training. Get them wrong — and most people do get them wrong — and you'll spend months diligently training in the wrong places, which is arguably worse than not bothering at all.
So this is the practical one. How to find your numbers, which methods work, which don't, and the mistakes I see runners make when they start out.
First, a reassurance. Heart rate training is one tool among many. It isn't compulsory, and it certainly isn't a sign that "real" runners use it and everyone else doesn't. Eliud Kipchoge ran 2:00:25 at Nike's Breaking2 in 2017 — the fastest anyone had ever covered the distance at that point — and reportedly didn't train to a heart rate monitor before that project at all. So if you take nothing else from this post: the data is your co-pilot, never the pilot. You are still flying the plane.
Why Generic Formulas Aren't Good Enough
If you've ever used "220 minus your age" or similar calculations to work out your max heart rate, throw it away. It's a population average dressed up as a personal number, and for any individual runner it can be out by twenty or thirty beats. I covered this in the last post — the spread in real max heart rates across people of the same age is enormous. Build your zones on a guess and every session inherits that error.
Even once you've got a genuine max heart rate, there's more than one way to turn it into training zones, and each method spits out slightly different numbers. So it pays to understand what you're actually doing rather than trusting whatever your watch decided for you out of the box.
The Gold Standard: Get Tested
If you want the most accurate picture — and you want to take the guesswork out entirely — get a physiological test done. There are two worth knowing about.
A VO2 max test tells you how big your engine is. It's run to failure, so you'll be harnessed in as you push to genuine exhaustion, and it gives you a true max heart rate as a by-product of getting you there.
A lactate threshold test is the one I'd point most runners towards. It isn't run to failure, which makes it a good deal more civilised, and it gives us your heart rate at lactate threshold directly. From that single anchor we can build the rest of your zones around your actual physiology.
Costs vary quite a bit depending on where you go, but if you're serious about training this way, the information you get back is genuinely worth it.
That said — not everyone wants to spend the money, and you don't have to. Here's how to get there yourself.
Doing It Yourself: Max HR or Heart Rate Reserve?
There are two common ways to calculate your zones: a percentage of your Maximum Heart Rate (%MaxHR), or a percentage of your Heart Rate Reserve (%HRR). I much prefer Heart Rate Reserve, and I'll show you why with actual numbers in a moment.
For either method you'll need your max heart rate. For the HRR method you'll also need your resting heart rate. Let's get both.
Finding your resting heart rate
This one's easy. Over the course of a week, find a quiet moment, lie down, and note your heart rate once it settles. Take the average across the week. It's worth re-checking every so often, because — and this becomes important later — as you get fitter your resting heart rate tends to drop. Most wearables like an Apple Watch or Oura Ring will track this for you.
Finding your max heart rate
This one's more interesting, by which I mean less pleasant. Your max heart rate is simply the highest number of beats per minute your heart can reach. It is not a measure of fitness — it's just your number, and everyone's is different. So don't read anything into whether it's high or low.
A few things it isn't. It isn't 220 minus your age. And it isn't the big number you saw at the end of your last parkrun, because on tired legs at the end of a 5K you physically can't drive yourself hard enough to reach it. A proper max test has to be short, sharp and done on fresh legs, so build it into your training on a day when you're well rested and can genuinely go for it. One important caveat before you try either test: if you have any underlying health issues, speak to a professional first. With that said, two options.
Test Option 1 — the hill. Find a hill that takes a good two minutes or more to climb, steep enough that you're flat out by the top. Warm up easy for 10 to 15 minutes. Then run about 5 minutes at threshold effort so that you arrive at the foot of the hill already working. As you hit the climb, hold your speed — and try to lift it — by pushing the effort up as your legs start to complain. Your heart rate will climb as you tire, and you should top out at your max somewhere near the summit.
Test Option 2 — the 800m (my preferred one). On a track or a flat stretch of road, run a hard 800m. Take the first 400m at around 95%, then in the final 400m simply empty the tank. You should hit your max somewhere in that second lap. If you don't quite get there, jog for 5 minutes and run it again.
With both tests your heart rate will usually peak and then sag slightly before you stop — that peak is your number. And yes, both of these are as rough as they sound. That's rather the point, and it's also why you won't want to repeat them often. You might also find you need to add a few beats to the number you get, because pushing yourself all the way to your true max is a skill in itself and most of us stop just short.
Calculating Your Zones (With Real Numbers)
Right — you've got your two numbers. Let's turn them into a zone. I'll use the Threshold zone as the worked example, which sits at 80–85% of Heart Rate Reserve, and I'll run the same person through both methods so you can see exactly why the choice matters.
Our runner:
Max HR: 180
Resting HR: 50
The %MaxHR method
Lower end: 80% of 180 = 144 bpm
Upper end: 85% of 180 = 153 bpm
Threshold zone by %MaxHR: 144–153 bpm
The %HRR method
First find Heart Rate Reserve — max minus resting: 180 − 50 = 130
Lower end: 80% of 130 = 104… then add resting HR back on: 104 + 50 = 154 bpm
Upper end: 85% of 130 = 110.5… add resting HR: 110.5 + 50 ≈ 160 bpm
Threshold zone by %HRR: 154–160 bpm
Look at the gap. Same runner, same day, two legitimate methods — and one puts their threshold ceiling at 153 while the other has their threshold floor at 154. That's not a rounding quibble. Train the %MaxHR zone thinking it's threshold and you'll be dawdling along well under the intensity the session was meant to deliver, wondering why you're not getting quicker.
I prefer %HRR for two reasons. It folds your resting heart rate into the sum, so it's more tailored to you — and because your resting heart rate drifts down as you get fitter, your zones quietly move with your fitness instead of staying frozen at a number you set months ago.
The Long Way: Building Zones From Your Own History
There's a third route, and it doesn't cost a penny — though it does cost patience. If you'd rather not do a max test or pay for lab work, you can build your zones from your own accumulated data over a few weeks of running, then do a handful of calculations to pin them down. These days there's a much easier way to handle the sums, which I'll come to at the end of the month — but the principle is worth understanding either way.
Whichever route you take, this is where harder isn't better really bites. Heart rate training only works if the whole plan hangs together. If your data says your threshold sits at 160 but you're plodding your easy runs at 150, something's wrong — either the easy runs are too hard, the threshold number's too low, or a bit of both. Those two figures have to make sense in relation to each other, or the whole structure wobbles. Building from history isn't as watertight as a proper test, but it's a perfectly good place to start.
Back Up the Numbers With Your Own Judgement
Here's the bit that ties the whole thing together, and it's the same message as always: run to effort, not pace — and read the number alongside how the running actually feels, never instead of it.
The tool for this is the Talk Test, which we bang on about for a reason. It's the simplest honesty check you've got. Threshold effort should be roughly a four-to-five-word-answer pace — enough breath for a short reply, not a chat. So if your calculated threshold zone says you're bang on, but you can only gasp out two or three words, the number is lying to you and the effort is too hard. Trust the test. It's the sense-check that stops a slightly-wrong zone quietly derailing weeks of training.
This is what I mean by the data being a co-pilot. The zones tell you where you should be; your breathing, your legs and your judgement tell you whether that's actually true today. When they disagree, don't blindly obey the watch.
Actually Training With It
We'll go deeper on putting this into practice soon, but the core of it is simple, and it's the same commitment I flagged in the last post. If you're going to train to heart rate, you have to trust the numbers and buy into the process — all of it, not just the easy days.
The cardinal sin is looking down mid-run, seeing the pace is a touch slower than you'd like, and deciding to run harder to "fix" it — ignoring the zone you carefully worked out. Do that and you've
thrown the whole thing away. You're back to chasing pace, back to the frustration loop, and the heart rate monitor is just an expensive watch face.
Slow and correct beats fast and wrong. Every single time.
Up Next in Heart Rate Month
So that's the how — how to find your zones, which methods to trust, and how to keep yourself honest once you're using them.
The last piece is making all of this genuinely easy to live with day to day. At the end of the month we'll be introducing something in the Full Potential app that takes the faff out of zones entirely — no spreadsheets, no re-doing the sums every time your fitness shifts. More on that very soon.
Thinking about an autumn race? If you want heart rate training built properly into your plan from day one — zones set correctly, sessions that actually fit together — drop me a line. We'll build a block that gets you to the start line fit, fresh and ready to run your best. [Book a coaching package →]