Heart rate training can be valuable. Knowing your target heart rates for different types of runs can help you make sure you’re not working too hard on easy runs — or too easy on hard runs.
Since most of your running should be easy, it’s important to know that you’re not going too hard on those easy days. And if you decide to crank the pace once or twice a week, knowing your target heart rates can help you find the right level of hard.
That said, I rarely tell any runners to run based on their heart rate. I instead encourage to run based on perceived effort or to use a pace calculator.How to Use a Pace CalculatorHow fast should you run?medium.com
Part of my problem with heart rate training has to do with the idea of the max heart rate. In general, max heart rate is tied to your age. There are several different formulas for it, but none of those formulas takes your fitness level into account.
So then, when you build your target heart rates for your training based on that max heart rate, your training levels have nothing to do with your actual fitness.
It always felt counter-intuitive to me that the target heart rates for a very fit person are the same as the targets for somebody who’s thinking about going for a run for the first time in years.
(Of course, running is full of counter-intuitive things, like how running slowly is a great way to get faster. I love that about our sport! But this one felt especially off.)
The data from my own runs bore this out. I do semi-regular mile time trials to check my fitness level, and I’ll enter either my most recent mile time or a recent race time into the pace calculator to get guidelines for how fast (or slow) I should run in a particular workout.
Based on both the pace calculator and my level of perceived exertion — that is, how hard the effort felt — I regularly finish runs that I’m confident were appropriately easy. Meanwhile, Garmin would tell me that I was overtraining, that my heart rate was too high, that I’d spent the entire run in zones 3 or 4 when I should have been in zones 1 or 2.
That didn’t seem right, and it was starting to stress me out.The Garmin Outage Is Good for RunnersData is fun but not necessarymedium.com
A Better Way to Do Heart Rate Training
Then I realized it was possible Garmin was wrong — or was, at least, using flawed data. Garmin’s training levels (as well as those of other fitness trackers and apps) are usually based solely on the max heart rate. As we’ve already seen, that’s tied to your age and has no relation to your fitness level.
There is, however, another metric that does take your fitness level into account. That’s your Heart Rate Reserve.
Heart Rate Reserve is an easy calculation:
your max heart rate — your resting heart rate
Here’s a guide to figuring out your max heart rate. And you can get your resting heart rate by taking your pulse as soon as you wake up in the morning. Or, if you sleep in a Garmin or Fitbit or other activity tracker, that service will be able to tell you your resting heart rate.
From there, getting your target heart rate zones is a little complicated, but if you use Garmin, you can have Garmin Connect do the math for you.
For reference, though, here are the zones:
Zone 1 (Warm-Up): 50–60% HRR + your resting heart rate
Zone 2 (Easy): 60–70% HRR + your resting heart rate
Zone 3 (Moderate): 70–80% HRR + your resting heart rate
Zone 4 (Lactate Threshold): 80–90% HRR + your resting heart rate
Zone 5 (Super Hard_: 90–100% HRR + your resting heart rate
An example for Zone 2, based on a Heart Rate Reserve of 150 and a resting heart rate of 50:
50% of 150 = 75 + 50 = 125
60% of 150 = 90 + 50 = 140
So this runner, to do a nice and easy run, would try to keep their heart rate between 125 and 140.
How This Improved My Running
When I changed my Garmin to use my Heart Rate Reserve instead of my Max Heart Rate, its statistics immediately seemed accurate. At the end of an easy run, it told me my heart rate stayed within Zone 2 the whole time. If I ran hard or conquered a hilly route, I could see my heart rate go into Zones 3 or 4, but not in a way that worried me, like before.
And the difference wasn’t drastic: Based on Max Heart Rate, my target for Zone 2 was between 113 and 132. Based on Heart Rate Reserve, my target is between 129 and 143. Clearly, for a lot of my run, I was hovering closer to 143, which made Garmin tell me I was up in Zone 3.
Now I know that my easy runs are appropriately easy. And given that most of your running should be easy — even if you’re trying to get fast — that’s an important thing to know.