Running, Triathlon
March 5, 2019

How To Calculate Heart Rate Zones

Setting heart rate zones on a watch

Heart rate monitors have been available for decades.

Polar first introduced its fingertip heart rate monitor, the Micro Heart Pulser in 1977 and since then heart rate technology has exploded.

Nowadays almost all running watches come equipped with a high-quality heart rate monitor taking measurements from the wrist or from a strap worn on your chest.

While the wrist monitors are quite accurate, they become less reliable as you begin to sweat and swing your arms, so I definitely recommend using the chest strap if you have one available.

But, first things first…

Why Is Measuring Heart Rate Important?

Heart rate is an objective measure of intensity and a way for your body to communicate with you.

Without it, you see the pace on your monitor, but you don’t know how hard you are working to achieve that pace. You might be running at 6:00 /km and doing it easy or you could be running at 6:00 /km and running hard.

The pace is the same but the physiological systems used and the benefits achieved from the session, vary greatly.

You see, the goal is not to run faster just by pushing harder, it’s to become more efficient so that at the same or lower heart rate, you’re able to run faster.

In order to achieve that, you need to train at the right intensities at the right time.

Heart rate is great because it puts some control around your training and helps you to balance the stress of life with the stress of training. It ensures you’re running at an intensity that is suitable for your current level of fitness at all times.

Heart rates are tagged to various markers of metabolic activity using heart rate zones and so long as you stay within the zone, you can feel confident that you’re training at the right intensity for you.

Sign up for Coached running or triathlon programmes.

Establish Your Heart Rate Zones

Inside Coached, we use 5 training zones to prescribe sessions to our athletes.

Z1: Easy
Z2: Steady
Z3: Mod Hard
Z4: Hard
Z5: Very Hard

Easy and Steady are aerobic zones used to develop your aerobic system. These zones are where you need to spend the majority of your time. 80+ percent of your training should be in zones 1 and 2.

Moderately Hard is at the ceiling of your aerobic capabilities and is used for your tempo sessions to improve your lactate clearance.

Hard and Very Hard are anaerobic zones that should be used carefully to improve your VO2max and power.

Lactate testing in a lab is the best way to establish heart rate zones but you can also use field testing or a good formula too.

Lactate Testing

Lactate testing is a test where levels of blood lactate are analysed at increasing intensities to determine threshold heart rate. Once you know your threshold heart rate, you can easily calculate your heart rate zones.

Field Testing

Field testing is a simple (but hard) test you can do on your own. If you’re just getting started, I don’t recommend this option as it puts your body under a tremendous amount of stress.

If you do want to use this option, run as hard as you can for 30-minutes following a short warm-up at a low intensity. Record your heart rate for the entire 30-minutes but take your average heart rate for the last 20-minutes. We discard the first 10-minutes as it takes a while for your heart rate to rise.

You can consider the average heart rate from the last 20-minutes as your lactate threshold heart rate and like with lactate testing, use that number to calculate your zones.

Formula

There are many formulas available online. Some are good while others are not so accurate.

When we needed a heart rate formula for our online training programme, we spent time in our lab testing the various formulas against real athletes lactate results. The outcome is the most accurate and simple formula we could find; a slightly modified version of Phil Maffetone’s 180-formula.

Calculate Your Heart Rate Zones

To make things super simple for you, we have created (with the help of Ming, one of our athlete’s and excel wizard) a heart rate calculator that you can use to calculate your heart rate zones, the Coached way.

Coached RunningBen PulhamBen Pulham is a former professional triathlete and the founder of Coached, a heart rate training programme that helps you optimise, track and enjoy your training.