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Heart rate training: What is it and why is it important?

February 4, 2026 | 5 min. read By Brooks Staff

When you first start training as a runner, your first goals will probably be to run faster and further – but there’s more to it than you think.

You may find yourself wondering why some runs leave you feeling tired and out of energy, while you breeze through others more quickly. More often than not, the answer lies in how hard your heart is working.

Your heart rate is more than how fast your heart beats during exercise. It’s also an indicator of how hard you’re working out and how much energy you’re using.

This is where tracking your heart rate zones can come in handy. It can help you train smarter, avoid injury and ensure you get the maximum benefits possible out of each run.

In this article, we’ll take a look at what heart rate zones are, how they work and how they can be used to reach your fitness goals.

What are heart rate zones?

When you’re working out – like running – your heartbeat naturally increases. As your heartbeat gets faster, you get closer to reaching your maximum heart rate. The different percentages of your maximum heart rate are split into ‘zones’, which then relate to the difference in training intensities. For example, power walking can get your heart working to about 60% of your maximum heart rate, which corresponds to zone 1.

The idea behind tracking your heart rate and zones is to be able to train both your aerobic and anaerobic systems, effectively boosting your heart health. By working within specific heart rate zones, you’ll be able to train effectively, without putting yourself at risk of injury.

You can track your heart rate with specific monitors, smart watch, or fitness tracker.

What is heart rate training?

Now we know what heart rate zones are, we can look into what heart rate training is, and how you can use it in your workouts. By tracking your heart rate, you can stay working out within specific zones, depending on your fitness goals. By keeping track of your beats-per-minute, you’ll know whether you need to train harder, or pull back on your intensity.

Keeping an eye on your real-time heartbeats ensures you can avoid any fatigue and overtraining, allowing you to recover faster.

How to calculate heart rate zones

As each heart rate is completely unique, you should work out your own maximum heart rate. One way to do this is: 220 – your age.

Once you have this, you can start to figure out the different percentages that make up each heart rate zone. To do this, you multiple your maximum heart rate (MHR) by the percentage range for each zone. For example, to work out heart rate zone 3, you would do: MHR X 0.7 or MHR X 0.8.

Heart Rate Zone	Percentage of Maximum Heart Rate	Intensity
Zone 1	50%-60% of maximum heart rate	Very light exercise
Zone 2	60%-70% of maximum heart rate	Light exercise
Zone 3	70%-80% of maximum heart rate	Moderate exercise
Zone 4	80%-90% of maximum heart rate	Hard exercise
Zone 5	90%-100% of maximum heart rate	Maximum effort into exercise

Heart rate zone 1

This is considered the ‘very light intensity’ zone, making up 50-60% of your MHR. You’ll likely reach this zone during warmups, cool downs and active recovery, as it keeps your heart rate higher than when resting, without putting strain on your muscles.

Heart rate zone 2

This is considered the ‘light intensity’ zone, making up 60-70% of your MHR, and is the zone where you can maintain your exercise for a prolonged period of time. When running, zone 2 should be considered your ‘easy’ run, where you can maintain a steady pace without feeling fatigue.

This zone is excellent for building aerobic endurance and should make up a large portion of your training, especially during base-building phases. However, most races – even marathons – are typically run in the higher zone 3 and above.

A run within zone 2 should be considered an ‘easy’ run, where you can maintain a steady pace without feeling fatigue. If your priority is targeting fat metabolism and mitochondrial density, this is the zone you want to focus your workouts on.

Heart rate zone 3

Zone 3 is the ‘moderate intensity’ zone, using 70-80% of your MHR. This comfortably difficult workout helps to build your speed and starts to fatigue your muscles. While you’ll still be able to speak in short sentences, this zone will put more strain on your muscles, forcing you to work harder.

If you want to improve your aerobic capacity and muscular endurance, zone 3 is the best option for this.

Heart rate zone 4

This is a hard pace but is still sustainable for shorter runs – like a 5k – using up 80-90% of your heart rate. Running in zone 4 should be intense and focused on aerobic activity, allowing you to build up your speed endurance slowly, over time.

Zone 4 is best for lactate threshold workouts and boosting your sustained power, allowing you to train for longer and further over time.

Heart rate zone 5

This is the maximum effort you can workout or run in, reaching up to your maximum heart rate. Sustaining effort in zone 5 is difficult and typically limited to short intervals or even events like a 5k. Trained and experienced runners may run an entire 5k race within the lower end of zone 5.

Training within this zone can also gradually help you boost speed and power. Zone 5 training also improves neuromuscular power and VO2 max.

Just like choosing the right running shoes, choosing which zone you should work out in is key to getting the most benefits. By managing your heart rate zones, you’ll be able to make your runs safer, effective and targeted towards your goals.

Disclaimer: Our writer's advice is intended for informational or general educational purposes only. We always encourage you to speak with your physician or healthcare provider before making any adjustments to your running, nutrition, or fitness routines.