Am I Doing Zone 2 Wrong

What is zone 2 exactly? How do I actually know if I'm in it? Most watches, whether it be a Garmin, an Apple Watch, a Coros, a Samsung, whatever you use, they all use what's called a 5-zone model, where zone 1 is the easiest, zone 5 is an all-out sprint, and zone 2 is on the easier end of the running spectrum, roughly 60-70% of your max heart rate.

That sounds simple enough, except there's a problem.

That calculation starts with your maximum heart rate, and your watch almost certainly doesn't know what your actual maximum heart rate is.

Most watches use a formula called 220 minus your age to estimate your maximum heart rate.

So if you're 35 years old, your watch takes 220, it subtracts your age of 35, and assumes that your max heart rate is 185 beats per minute.

The problem is that that formula has a standard error of plus or minus 12 beats per minute, which means your watch could be off by 12 beats per minute in either direction.

And for older runners, it can be off by as much as 40 beats per minute.

That's right, 40 beats.

That's not a rounding error.

That is a completely different zone.

And here's the thing, every single zone on your watch is calculated off of that one number.

So if your estimated max heart rate is wrong, your zone two range is wrong, your zone three range is wrong, all of it is wrong.

Now, I'm not telling you to go throw your watch in the trash.

I use mine, my Garmin 4Runner here on every single run and I love it.

But I am saying that you shouldn't treat those numbers like they're the gospel because they're built on an estimate.

And as we'll get into in a few minutes, there's actually a much more reliable way to know if you're in zone two.

And it doesn't require any watch at all.

And honestly, it's not really your watch's fault.

It's just trying to use an estimate that works for the whole population.

But heart rates are wildly different from person to person.

For instance, my resting heart rate sits around 54 beats per minute.

My wife's resting heart rate is around 78 beats per minute.

Same house, same diet, same lifestyle, completely different heart rates.

So not only is your watch working off of an estimate, but even if it wasn't, you still couldn't compare your heart rate numbers to anyone else's.

Your zones are yours alone, and nobody else's numbers mean anything for you.