wearing a heart rate monitor

Heart rate training was all the rage in the 80s and 90s. Power training is becoming more popular now, at least for cyclists, but heart rate monitors are still way cheaper than power meters (and monitoring your heart rate will always have its place).

A heart rate monitor is not an absolutely essential tool, but it sure is nice to have.

Regardless, all athletes should understand the concept of heart rate training, which is explained here.

How Your Heart Works

First of all, it’s essential to understand how your heart works. Not specifically how it pumps blood, rather, what happens during exercise.

At rest, your heart probably doesn’t work very hard. If you’re a trained athlete, it might only beat half as often as a sedentary person. But once you start moving around, exercising, it has to work a little harder because you need more oxygenated blood going to your muscles.

So for any given workout or intensity level, your heart is doing a certain amount of work, and we can use that as a relative measurement for how hard we are working during training or racing.

How do you measure that? With a heart rate monitor, of course.

How a Heart Rate Monitor (HRM) Works

A heart rate monitor, or HRM, consists of two parts – the actual heart rate monitor and the display unit.

You wear a chest strap that monitors your heart rate in real time in beats per minute (bpm). The strap transmits that information and displays it for you on a wrist or handlebar mounted device.

You can count your heart rate (pulse) yourself by putting your finger on your wrist for 60 seconds and counting how many times you feel a beat. But you can’t do that during exercise, so it makes sense to wear a device that monitors it for you.

Why You Should Train with a Heart Rate Monitor

Your heart rate is a good way to gauge intensity. Checking it periodically during exercise gives you an idea of how hard you’re working.

Without it, you’re just going on how you feel (which does work to some extent, but it’s so hard to compare from one person to another).

When you know your heart rate, you can structure your workouts around it. And it makes for better communication between athletes and coaches.

A Simple Look at Heart Rate Training Zones

Heart rate training is broken down into training zones. Typically there are five zones, and each zone represents a certain exertion level.

  • Zone 1 is active recovery.
  • Zones 2-4 are your endurance pace rides where most riding takes place.
  • Zone 5 is very hard riding (sprints and intervals.)

We’ll get into much more detail in the next sections.

Determining Your Heart Rate Zones

Since we are all different physiologically, heart rate is going to be different for everyone. It’s a personal thing.

Zone 4 for you is not necessarily zone 4 for me, in terms of how fast our hearts are going to beat, even if it’s relatively the same intensity level. You might be riding with someone, a long endurance ride in zone 2, with one of you at 135 bpm and the other at 145 bpm – and it’s an equivalent exertion level.

It’s all relative to your Maximum Heart Rate (MHR).

But, figuring out your MHR sucks! And you’ll probably get it wrong anyway. Reaching your max during exercise is extremely difficult. Like, you might black out if you do!

Oh, that whole “220 minus your age” formula? That’s no better than a guess. It’s hardly even accurate for sedentary people. It won’t be anywhere near correct for an athlete.

So let’s forget MHR entirely. Instead, figure out your Lactate Threshold Heart Rate (LTHR.) Your lactate threshold is sometimes referred to as anaerobic threshold, or even functional threshold, and it corresponds to the highest average heart rate you can maintain for 45-60 minutes.

In a later section I’ll explain exactly how to perform this on-bike test.

In the mean time, let’s assume your LTHR is 163bpm.

The training zones you will use are calculated according to this chart:

Heart Rate Training Zones Chart

Zone Description Target HR (% of LTHR)
Zone 1 Active Recovery < 81%
Zone 2 Aerobic Threshold 81-89%
Zone 3 Tempo 90-95%
Zone 4 Sublactate Threshold 96-99%
Zone 5a Lactate Threshold 100-101%
Zone 5b Aerobic Capacity 102-105%
Zone 5c Anaerobic Capacity > 106%


Sticking with the example…

Your range for Zone 1 is: 0.809 * 163bpm

That comes out to: 131bpm or under

For Zone 2: From 0.81 * 163bpm to 0.89 * 163bpm

That comes to: 132bpm – 145bpm

And so on.

Or just download this Excel spreadsheet that will calculate these zones for you. All you have to do is put in your LTHR and it will calculate the corresponding zones!

Heart Rate Training Zones Explained

These are the zones as laid out by Joe Friel. If you base your training around what’s found in The Cyclist’s Training Bible, Joe Friel’s book, you’ll be using these zones.

It’s a great book and you should own a copy, so that’s why I’m referencing his zones.

Here are the finer details of each of the five zones:

Zone 1 – Active Recovery
You’re up and moving around, but you are riding at a recovery pace. This zone is used for warm ups, cool downs, and recovery rides. Riding at this pace is not a workout.

Zone 2 – Aerobic Threshold
Riding at this pace is very comfortable and quite useful for building aerobic fitness. It’s your typical endurance pace for long rides of 4-6 hours or more.

Zone 3 – Tempo
This pace is a bit faster, but still easily maintained for hours.

Zone 4 – Sublactate Threshold
This is where it starts to feel noticeably harder. You have to concentrate on going faster so your heart rate doesn’t drop back into zone 3, but it’s not a difficult pace.

Zone 5a – Lactate Threshold
Zone 5 is where you go from long rides to intervals. Zone 5a is tough, but it’s a very important zone for training purposes. Training here typically consists of 20 minute intervals.

Zone 5b – Aerobic Capacity
This is where you will be at for shorter intervals, perhaps 2-5 minutes in length.

Zone 5c – Anaerobic Capacity
These are the most intense intervals, lasting only 30-90 seconds, or sprints.

When you see the terminology on a training plan, it will make sense.

How to Determine Lactate Threshold Heart Rate (LTHR)

Here it is, what you’ve all been waiting for! The actual field test for LTHR.

It’s not complicated, but it’s tough, both mentally and physically.

Here’s what you do:

  • Find a course consisting of flat roads that are [mostly] free of interruption.
  • Ride all out for 30 minutes. (It should be done as if it was a 30 minute race against the clock.)
  • Take your average HR for the last 20 minutes of that ride, and that’s your LTHR.

It’s simple.

Just in case you were wondering, it must be solo. Doing this as a part of a race or with training partners will change the outcome because it adds in too many distractions.

Also, for accurate results, you have to go hard the whole time. Don’t go easy for the first 10 minutes just because your heart rate for that time period isn’t recorded. At the same time, don’t start at a sprint and then slow down too much. Aim for a steady effort.

You have to wear your heart rate monitor to capture the data. After the ride, download it to your computer using whatever software came with it or whatever program you happen to use for this analysis.

When you find your average HR for the last 20 minutes, that gives you a good approximation of your LTHR.

If you don’t have software, no problem. Just remember to push the “lap” button 10 minutes into the test. That will capture the last 20 minutes as a standalone interval. Viewing your average heart rate for that portion is your LTHR.

You’ll do this test multiple times and get better at it. If you’re new to it, go ahead and do it every month until you get a somewhat consistent outcome.

You’ll notice that there’s a certain HR you can maintain with concentrated effort, but if you go just a few beats higher, you’ll be struggling and have to slow back down. Your LTHR will be just about that number.

That’s it!

Note: Your LTHR is sport-specific. So you have to do a cycling test and/or running test and/or swimming test.

Choosing a Heart Rate Monitor

The last step here before going out and determining your LTHR is to choose a heart rate monitor!

These days they’re pretty cheap. Sure, you can still find some that cost $450, but there are quite a few basic ones under $100. Sometimes they’re on sale for under $50.

Keep this in mind when making your decision:


Stick with a trusted brand name that’s going to be both accurate and reliable. Polar, Garmin, and Suunto are big names that have been around. Sigma Sport is less popular, but offer great value and low prices, so I’m a big fan. Timex is a common name, and they make some good stuff, and some junk, too.


Most of your comparison shopping will consist of making sure the specific model includes the features you’re looking for. Here are some useful features:

  • Current heart rate
  • Avg heart rate
  • Target zones with audible alert
  • Time in target zone
  • Stopwatch and lap/split times
  • Calorie burn
  • Computer software/interface

Also important is to make sure your heart rate monitor plays nicely with the rest of your equipment (if you use multiple devices).

For example, if you have a Garmin Edge, you can just get a Garmin heart rate strap and you’re good to go. It’s usually included with Garmin GPS units if you get a package deal.

Or you might want something with ANT+ wireless or bluetooth connectivity to interact with other devices, head units, or your smartphone.

At the same time, you might prefer a standalone device. For instance, if you plan to track both cycling and running with it, something linked to the Edge on your bike might not be as convenient as an HRM on your wrist.

Some HRMs That I Like

The most popular setup these days is to get a Garmin Edge or Garmin Forerunner with a heart rate kit. Then you get both a GPS and an HRM in one.

But there are some standalone HRMs, too.

Polar FT7
A trusted brand, lots of features.
$72, Amazon.com

Polar RS300X
The new model which replaced the popular RS100.
$79, Amazon.com

Suunto Quest
Excellent monitor with more features than you’ll ever need.
$209, Amazon.com

Problems and Shortcomings of Heart Rate Training

Why has heart rate based training fallen out of favor in recent years? It’s simply not as good as power meter based training.

So many factors can affect your HR, not just training stimulus. So your heart rate at a given power output is going to vary day by day. It depends on how rested you are, your mental state, hydration levels, and even heat and humidity. A power meter is far more accurate.

And Rating of Perceived Exertion (RPE) can be just as useful, albeit different.

Think of it like this: Heart rate is how hard your body is working, RPE is how hard you feel like you’re working, and power is the actual work produced from your effort.

When it comes to training, it’s nice to monitor your actual work output, which is not affected by weather conditions or hydration levels. If you are producing 300 watts, you’re producing 300 watts – doesn’t matter if it’s freezing cold or in the sweltering heat.

Also, power meters give you instant feedback. If you are sprinting all out, your power meter will record that. However, it takes your HR a while to respond to changes in exertion. Say you do a sprint – your HR won’t be high until after you’ve already completed the sprint.

But when power meters are generally $700-1200 or more, heart rate training looks pretty good!

My Final Verdict on Heart Rate Monitors Is…

Get yourself a heart rate monitor!

If you understand what HR shows, and its limitations, it’s a useful tool in your toolbox.

Wear an HRM for a year or two, you’ll get a good sense of how your heart responds, and you can almost predict what your HR is without looking. Then you can go by feel, if you so choose.

But, even if your training plan is based around power, I think it’s always a good idea to monitor your heart rate. If it looks abnormally high, that could be an indicator you need a rest day.

Training plans from Coach Levi are available based around HR, RPE, and power, so they work for you, regardless of your device preference!

Show References

Do you train with a heart rate monitor? Or have any further questions? I’d love to hear your thoughts in the comments section!
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