Understanding Heart Rate Zones and How They Impact Your Training

Using Heart Rate Zones can accelerate your training and lead to huge fitness breakthroughs. So what are they – and how do you use them?

Zone training: It’s been used by performance-minded endurance athletes for a while. But recently, it’s been catching on with active people at every level. You may have seen headlines or heard friends declaring “zone 2 is the best for burning fat,” for instance. 

So what are zones? And how do you use them?

Before you read on, though: You can only see zones on Strava with a subscription. If you haven’t yet, sign up for Strava and subscribe or start your 30-day free subscription trial.

Full disclosure: We’ll be focused mostly on running / walking zones here. Cycling zones are a little different – we’ll cover them briefly later.

What Are Zones?

Zones – short for heart rate zones – are effort ranges based on your heart rate. To put it simply, they measure how hard you’re working  – zone 1 (Z1) is super easy, and zone 5 (Z5) is hard to all-out.

And to put it less-simply?

“Zones are a way to think about how your body is using energy and what the adaptation and stimulus ends up being,” says David Roche, a pro trail runner who coaches beginners and fellow pros alike at Some Work, All Play.

Running at different intensities isn’t a new concept, but zones give us a universal language to talk about different types of workouts and a framework to maximize our training gains from them. 

Zones are based on effort – not pace. The pace each zone produces will vary by individual. 

Let’s illustrate it this way: Imagine you’re running with former marathon world record-holder Eliud Kipchoge. Don’t be shy – he might be the nicest person on the planet! But he’s also the only one who’s run 26.2 miles in under two hours. So if you both started running in Z2, he’d quickly pull away from you, because the pace required to get his heart rate up to Z2 is probably around 5:30 per mile – that’s nearly all-out even for most highly-trained runners!

On the other hand, if you and the marathon GOAT were running the same pace, you’d be in different zones. Let’s say you’re both cruising down the road at a 7:00 per mile pace. He’d be chilling in Z1, maybe chatting your ear off, while you might be red-lining in Z4, speaking only in short clips, tasting metal, just trying to keep up.  

Why Are Zones Important?

Being intentional with different effort levels and when you use them can help you get fitter and faster. 

Let’s switch the Coach Roche filter back on: “Knowing your zones and applying them properly can help your body burn more fat at higher outputs and stimulate mitochondrial development and efficiency,” he says. “It can help you put out the same intensities with lower effort.” 

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For example: If you have limited time and want to burn fat, you might aim to do everything in Z2 and get the most bang for your buck. 

On the other hand: If you’re trying to set a new 5K PR, you can gain speed and efficiency with workouts in Z3-5, but you also have to use Z1-2 to absorb and recover from those hard efforts. 

What Are My Zones?

The easiest way to see your zone is to use a heart rate monitor. If you don’t have one, you can go off effort-based cues.

These zones can vary from person to person, but here’s a generally-accepted guideline:

Tracking Your Zones on Strava 

Subscribers who use a heart rate monitor can see a detailed breakdown of their zones from each activity. 

On mobile, go to an activity’s detail page, tap View Analysis and scroll down to Heart Rate Zones. (Pace Zones are another matter – fun and useful, but not what we’re focused on here.) 

To see your zones on desktop, click into the activity details – then on the left, under Analysis, click Heart Rate.

This gives you a breakdown of the zones you hit during each activity. Use this to see the proportions of the workout you spent in each zone, gauge whether you accomplished what you wanted to, and plan the next training session.

Your zones are based on your maximum heart rate, which Strava estimates based on your age. But if you know your metrics are different, you can edit your maximum heart rate and even customize your zones on desktop – in Profile, go to Settings then My Performance to change them. 

A Quick Note on Cycling Zones

Cyclists who track heart rate can use the five-zone scale based on heart rate we’ve already discussed. But they also sometimes use a seven-zone scale based on power output (in watts).

Here is what power zones look like, with examples based on a very good amateur cyclist with an FTP of 300 watts:

• Z1: Active recovery. Up to 55% of FTP. (<165 watts.)

• Z2: Endurance. 55-75%. (165-225 watts.)

• Z3: Tempo. 75-90%. (225-270 watts.)

• Z4: Threshold. 90-105% (270-315 watts.)

• Z5: V02 Max. 105-120%. (315-360 watts.)

• Z6: Anaerobic. 120-150%. (360-450 watts.)

• Z7: Neuromuscular. 150%+ (450 watts +.)

Why are there seven instead of five?

Heart rate zones are based maximum heart rate, while power zones are based on something called functional threshold power (FTP) – roughly the power you can hold for one hour. 

If you’re running or riding in heart rate Z5, by definition, it’s at or near your max, so you can’t push harder. But if you’re cycling at power Z4 or Z5 – your FTP – you can go harder if the effort lasts less than an hour. In short sprints, you could very well hit double your FTP, and pro cyclists might hit triple. So those on two wheels needed to define two additional power zones to accommodate these even harder efforts.

RELATED: Feel the Power: Know your Training Zones & How They Should Feel

Cyclists can use either heart rate or power zones, depending on their preference. But some use a combination of both – for example, you might use heart rate for Z1 or Z2 training to ensure you aren’t pushing too hard to hit a certain power, then switch to power for workouts in Z3 or higher. 

Pro tip: You’ll need to track your power output with a power meter or a smart trainer to see your power zones. And like heart rate zones, they’re only available for subscribers. 

Using Heart Rate Zones to Improve Performance

Now that you know what zones are and how to calculate yours, it’s time to try applying them to your own training. Stay tuned for the next article where Coach Roche gets into the details of how beginner, intermediate and advanced runners alike can benefit from using zones.