Do you go for a run and finish questioning if your heart rate is too high or too low, what that means and how you can train better? We're here to help leaving you informed and ready to take on your training.

Fitness watch on wrist displaying heart rate, calories and distance.

Understanding heart rate

Our heart beats multiple times every minute to pump blood around our body, carrying oxygen to give our cells energy to function. When we need more energy, for example when we are moving faster, we need more oxygen to power our muscles and as a result our heart has to beat faster.

As we get fitter, our body becomes more efficient at this process and so we can do the equivalent load with a lower heart rate (or we can do more with the same heart rate). When it comes to running, over time as we get fitter, we might find that running at the same 'easy pace' after 10 weeks of training sees a drop in our average heart rate. Additionally, when we're pushing the pace we can run faster without setting a new maximum heart rate.

Drawbacks of training with heart rate data

Setting the intensity of your runs based heart rate has quite a few problems

Inaccuracy

Firstly, most wrist-based HR data is inaccurate. Whilst it can be a good indicator of fitness and your true HR, it is also affected by weather, sweat or even how tight your watch is. We would suggest only relying on your HR data if training from a chest-based or arm-based HR monitor.

Lagging data

Secondly, HR is a secondary data point. Your heart rate changes as a result of changing other factors. Should you want to increase your HR you can't just increase it; you have to run harder and then wait a while see your HR increase. If you stop, it can take quite some time for your heart rate to come back down again. As a result it is much easier to work off pace. If you'd like, you can look at your current heart rate at the prescribed pace and try to maintain this heart rate if the terrain or elevation changes.

Individuality

Finally, HR data has huge individual variation. There are a huge number of factors which affect HR including genetic factors. As a result if you notice your heart rate is higher than a friend who you are faster than, do not panic! As a result we would suggest being aware of your heart rate and noticing if something is out of the ordinary, but only compare it to what yours typically is.

An image of several runners about to set off for a time travel. The runners are ready to start their watches

How to train using heart rate

To train with heart rate, it's common to split your intensity level up into heart rate zones. To calculate this, you first need to understand your maximum heart rate.

The most simple way to estimate your max heart rate is 220 - your age. For example, a 40 year old would have a max heart of 220 - 40 = 180bpm. A better way to find your max HR is to do a field test. You should not do a field test unless you are uninjured and are used to raising your heart rate to maximal levels. A field test should be done whilst wearing an heart rate monitor and a medical professional should always be consulted first. An example of how to perform a field test is to:

  1. Warm up for 15-20 minutes

  2. Find an area you can run along with no obstacles, preferably a hill that will take at least 2 minutes to run to the top of at a maximum pace. Run up the hill for 2 minutes at a steady but challenging pace that you estimate you could hold for 20-30 minutes.

  3. Run up the hill at a pace you think you could hold for 3km or 1.9 miles. Watch your heart rate. The maximum value of this effort should be about 10 beats fewer than your maximum heart rate value.

  4. Run up the hill at a maximum effort for 45 seconds to a minute. You should achieve your maximum heart rate.

  5. Cool down for at least 15 minutes.

Once you know your maximum heart rate, you can calculate your heart rate zones. There are many differing opinions of exactly what percentage of your maximum heart rate each zone should be, but generally speaking there are 5 HR zones which are as follows:

Zone

Description

% of max HR

Duration you should be able to hold this HR for

Zone 1

Very Easy

50-60

6+ hours

Zone 2

Easy

60-70

1-3 hours

Zone 3

Moderate

70-80

40-90 minutes

Zone 4

Hard

80-90

6-40 minutes

Zone 5

Very Hard

90-100

Less than 5 minutes

When thinking about training with heart rate, you can think about what type of runs match with which heart rate zones.

Generally speaking:

Easy runs should be in Zones 1 and 2

Tempo and Interval runs should average out to be Zone 3 or Zone 4, however you may spend some time in Zone 5, especially during intervals

Most races will be run in Zone 3 and/or 4 depending on their length.

You can use this as a guide, particularly when doing easy runs to ensure that you are not pushing yourself too hard. Additionally, if you are running in a particularly hilly area you may find that the pace targets are too challenging or too easy depending on the gradient you are running on. In these cases it may be best to train with heart rate and try to keep your heart rate consistent instead of your pace. For example, when doing a hilly easy run, you should try to ensure your heart rate remains in Zone 2 or below- even if this means you need to walk a particularly steep hill. Additionally, when doing intervals in a particularly hilly area it can be best to already know what heart rate zone you are usually in when doing a 1km effort for example, and then replicating this.

How should I look at and understand my own data?

When it comes to understanding your own heart rate data, there are some general patterns you should expect to see:

  1. As you get fitter, your resting heart rate will go down. Your resting heart rate is the lowest amount of blood your body needs to pump while you are relaxed and not exercising. The average resting heart rate is between 60 and 100 beats per minute, however many runners will have significantly lower heart rates than this as their body has become so much more efficient at delivering oxygen to cells. As a result, overtime you should see your heart rate lower when running the same sessions from the past.

  2. Your heart rate should go up when training harder, for example when training in the heat, running uphill or running on trails rather than tarmac

  3. When your heart rate is higher than usual, it may indicate that you are overtraining or ill. If any of these are the case, it is best to take a few extra days of rest.

Let us know if you'd like the option to follow your Runna plan with HR instead of paces, we'd love to hear your feedback!

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