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Heart rate running: Why you need to run slower to run faster.

July 31st 2025

If you’ve ever wondered how elite endurance athletes seem to go further, faster—and with less effort—the secret might lie not in how hard they train, but how smart they train. Welcome to the world of Zone 2 running: a low-intensity, high-impact method that builds your aerobic engine, burns fat more efficiently, and strengthens your cardiovascular system without burning you out.

In this month’s blog post, we’ll explore what Zone 2 heart rate training is, why it’s become a cornerstone of successful endurance programs, and how you can harness its benefits—whether you’re training for your first 5K, aiming to boost your marathon performance, or just looking to improve your overall health and stamina.

WHAT IS HEART RATE ZONE 2 RUNNING?

First and foremost, let’s start with the fundamentals of zone 2 running and what it actually is.

Zone 2 training is a specific type of cardiovascular training which requires you to stay at a light intensity and keep your heart rate within a specific range. Typically, you will find your zone 2 is between 60 and 70% of your maximum heart rate.

Below is a table for you to see the different heart rate zones.

ZoneIntensity% of Max HRPrimary benefit
Zone 1Very light50 – 60%Recovery, warm ups and cool downs
Zone 2Light, sustainable60-70%Aerobic endurance, fat burning
Zone 3Moderate70-80%Cardiovascular efficiency
Zone 4Hard80-90%Lactate threshold, improved speed
Zone 5Very hard, max effort90-100%Anaerobic Capacity, sprint power

WHAT IS HAPPENING WHILST YOU RUN IN ZONE 2?

When running in zone 2 your body is using its aerobic energy system, which uses fats for fuel, rather than carbohydrates, which is what your anaerobic energy system uses for fuel.

However that’s not the only thing happening and under the hood much more is taking place:

Mitochondrial adaptation: Your cells produce more and healthier mitochondria, boosting your ability to generate energy efficiently.

Improved fat oxidation: Your body becomes better at burning fat for fuel, which is crucial for long-distance efforts.

Lower lactate production: You stay below the point where lactate accumulates quickly, allowing for longer training sessions without fatigue.

WHY IS ZONE 2 RUNNING IMPORTANT?

There are several reasons as to why zone two running is important and not just the latest fad you should jump on. Like previously mentioned it uses fat as it fuel, so if you’re looking to lose weight or fat then it is a really straightforward way of doing so. You also build up an aerobic fitness base, giving you the ability to run for longer, perfect for when you are training for a long distance running event.

It enables a greater recovery as the ‘work’ you do is less demanding on your body resulting in better energy for other runs or activities. More specifically for running; if you are following a training block and require some speed, tempo or interval sessions the slow steady zone 2 running compliments these really well as they allow your body to be fully recovered and ready for the hard work required during the more intense sessions, which in consequence is making you faster. This is where the saying comes ‘you have to run slower to run faster’.

Finally it is also important for health reasons, not only helping improve running performance. It improves cardiovascular strength, lowers your resting heart rate, improves insulin sensitivity and improves blood flow.

HOW CAN YOU START ZONE 2 RUNNING?

To put it simply, just start running. The best way to build mileage, confidence, stamina and endurance in running is to just start. However to be more specific to zone two running you just need to plan ahead and have a way of measuring your heart rate.

The reason to plan ahead is that it’s much easier to actually do something if you have set aside the time to do so. So by working out what days you are going to run, and what run that week is going to be dedicated to zone 2 gives you more chance of completing the appropriate runs. Resulting in the benefits to your performance.

Measuring your heart starts with working out what your zone two is, like previously mentioned your zone 2 is 60-70% of your maximum heart rate. So firstly we need to work out your maximum heart rate. The rule of thumb  is that it’s 220 minus your age.

For example; you’re 30 years old:

220 – 30 = 190.

60% of 190 = 114

70% of 190 = 133

Therefore, generally speaking a 30 year olds zone two would be between 114 and 133 beats per minute.

However; to throw a massive spanner in the works, I think this is WRONG.

How can every 30 year old in the world be painted with the same brush and expect to have the same maximum heart rate? It’s impossible in the opinion of the latest research.

The best way to find your maximum heart rate is to use your smart watch application on your phone, find an intense workout, whether it be a run, cycle, gym session or HIIT (High Intensity Interval Training) class and see what your maximum heart rate was. The more workouts you look at the more data you will collect. From here, just use the calculations above (with your new maximum heart rate) to work out what 60-70% of your max heart rate is.

Whilst trying to run zone two, the most accurate way to measure it is by using a heart monitor chest strap, which links to your smartwatch. The next best way is to use the smart watch itself as a heart monitor. Finally, if you do not have the latest gadgets then a good way to tell if you’re in your zone 2 is whether you could hold a conversation or breath in and out through your nose, just to note, these measurements are not as accurate as the watch or heart rate monitor but they are a good indication as to whether you are working at an ‘easy’ pace.

When you have worked out what your zone two is and you’re ready to get training you may wonder: ’How much zone two running do I need to do?’ The best place to start is around 70-80% of your weekly mileage if you are looking to build up endurance, for example, if you are starting a long training block for an event in several months’ time. If you run leisurely then it would be good to incorporate it into your runs with about 50% of your mileage.

Conclusion

To conclude this month’s blog post, zone two running is a form of cardiovascular training which builds up running endurance. Whilst it is considered an ‘easy run’ it is a vital part of training. It allows runners the chance to clock up miles without using as much energy, therefore leaving them feeling fresh for the more intense workouts.

So if you are a keen runner, whether you are looking to build up mileage, start training for a race, or just looking to improve your heart rate and resultantly not feel so tired after every run then look no further than zone 2 running. Like previously mentioned, it does not take a great deal to get started and in a matter of weeks you can see a huge benefit.

Sometimes you need to run slower to run faster!

Jack Underwood

Sports Therapist