What Does a Heart Rate Monitor Tell You?


One question I often get asked is ‘how do I use my heart rate monitor?’ or ‘what are heart rate training zones?’ or ‘how do I set and use heart rate training zones?’. With this in mind, I thought it would be useful to write an article on what a heart rate monitor is used for, what you can learn from using one and perhaps more importantly, how can a heart rate monitor benefit your exercise and training?

So what does a heart rate monitor tell you? In simple terms, a heart rate monitor measures the rate at which your heart is beating at any given time. This is useful because it gives an objective measurement of how hard you are exercising at that time that can be used to help you exercise at the best intensity to meet your goals.

Many people have a heart rate monitor but are unsure of how to use it, or are considering buying one but aren’t really sure how to go about it. Like many things, most monitors can be used to guide anybody’s exercise needs but certain features can be useful in certain circumstances. This article isn’t about how to choose a heart rate monitor but it is about how you can use a heart rate monitor, which is clearly helpful if you need to choose one.

Don’t worry about training zones to start with

We can think about training zones later but the best way to get started is just to use your monitor and see what happens.

Go out and use your monitor, see what it does and have a look at any data that it has recorded. In this way, you can start understanding how it relates to reality, which is much more important than learning a lot of theory, at least initially. Do some hard sessions and some easy sessions and some sessions with short hard efforts and longer hard efforts to see what happens. If you monitor has GPS you can see how your heart rate compares to your speed and how it changes with hills.

Hilly trail race

Hilly trail race

Interval session

Interval session

You can see from the two graphs that heart rate is much slower to change than speed or power (if you are lucky enough to have a power meter). Also that you can be running faster with a lower heart rate or slower with a higher heart rate, this is most obvious on hills. If you look at the trace for the interval session you can see that in the last interval the heart rate drops more slowly than in the first, so you can learn that as you get tired you recover more slowly.

Now you have an idea of how your heart rate monitor works, how it records data and how your heart rate relates you your exercise you can better understand how to use it.

Heart rate training zones

Heart rate based training zones, proposed by Andy Coggan

Heart rate based training zones, proposed by Andy Coggan

Heart rate training zones are simply a series of zones that relate to different levels of effort. There are many different ways to calculate the zones but it doesn’t matter very much which method you use, the most important thing is to choose something that makes sense for you and then stick with it so that you understand how to use the zones to get the best out of yourself. I also recommend keeping it simple, at least initially and if need be you can make some refinements later.

I like to use the zones proposed by Andy Coggan, which you can calculate using the TrainingPeaks application either on your phone, tablet or desktop/laptop. With just 5 zones, these are nice and simple but also allow you to target the important energy systems.

To calculate the zones you need to have an estimate of what is called your threshold heart rate. This is just the heart rate you can sustain for a reasonable amount of time such as 40 minutes so you can determine the value by going out and working as hard as you can for 40 minutes. You can also get a reasonable estimate by finding your maximum heart rate and taking 90% of that value. Don’t worry too much about the initial values, you can refine them as you collect more data.

How do I use heart rate training zones?

Once you have calculated your training zones you can start using them both to plan and analyse your training.

Once again, the best way to do this is to think about what you want to achieve rather than to simply follow a recipe that may or may not be right for you. Do you want to run/walk a 5km Parkrun, take part in a 100 mile cycling event or something else? How you train will depend on what you are training for, it seems obvious but it is surprising how people often miss this important point.

Look at your data and think about what you know about training zones. You can sustain your effort in zone 4 for around 45 minutes, around 5 minutes for zone 5 and longer for the lower zones. By training, you can work for a very long time in zone 1, several hours in zone 2 and maybe build up to 2 hours in zone 3. With these values in mind you can think about what zones you will be working in to achieve your goals.

Making a training plan is then a case of doing a lot of your training in the zones that are most important and adding in a few sessions per month in the other zones because it is most effective to include a bit of everything since all the zones have an effect on the other zones, but to varying amounts.

The other thing I would suggest is to be cautious and spend more time in the easier zones than you might initially think is appropriate. You can get very fit by spending 99% of your time in zones 1 and 2. You are also more likely to experience excessive fatigue or injury from training at the higher intensities.

The detail of creating a training plan is beyond the scope of this article but if you spend some time thinking about the details above you will have all the necessary information to create a very effective training plan.

Measuring Improvements

In any situation where you have goals, it is important to know whether things are working as you want them to. You need some way of measuring whether you are on the right track.

If you are training for an endurance sport then the speed at which you travel or the time it takes you to cover a given course is often the best way to see how things are going.

With a heart rate monitor you can do this in several ways:

  • Maximum effort time trial - measure your best time round a given circuit and see if you are improving. Use the same circuit each time, make sure you are well rested and that weather conditions aren’t a major influence;

  • Sub-maximal effort time trial - similar to the maximal effort but do the circuit in a lower heart rate zone and see whether you are improving. Surprisingly, you can be more or less well trained in different zones so this can be a great way of checking how you are getting on at levels that are more specific to your goals;

  • Look at your training data and see if you are getting faster at given heart rates or going the same speed with lower heart rates.

The best way is of course to use all three methods and as with training, use the lower intensity measurements more frequently. You can look at training data all the time, do a sub-maximal test every couple of weeks and a maximal test, maybe once every 6 weeks.


A heart rate monitor can also give an early indication that you are getting overly tired and in extreme cases, approaching the onset of chronic fatigue syndrome. If you are struggling to get your heart rate up to the higher training zones or it doesn’t rise as quickly as usual, it can be a sign that you are either overtired or getting an illness. An unusually high heart rate for a given level of effort can also be a sign that something is wrong.

It is important to pay attention to these signs and once again, err on the side of caution. The most important factor in building fitness is consistency over an extended period of time. The best way to be consistent is to remain healthy and avoid overdoing things to the extent that you have to stop for extended periods. It is much better to take a day or two off and recover than have to take months off to recover from illness or injury.

Related Questions

Is it better to train with pace using a GPS device? As technology becomes more affordable and many heart rate monitors and phones have built in GPS, the option to measure and use many different types of data increases. Which is better? The best method of training is the one you understand and can use effectively. Pace has advantages over heart rate and vice versa. In the absence of hills, pace is a great way of planning, executing and analysing training but on hilly courses or those with mixed terrain, it varies in ways that are not proportional to effort and in these areas, heart rate can be better. If you want to use pace, the process is the same as I have described for heart rate so why not give it a go and see what works best for you and your event.

Is it better to train with a power meter? Power meters are becoming increasingly affordable and increasingly popular. In cycling, they provide measurements that are directly related to your output, in running the data is not so simple as certain assumptions must be made. If you can afford a power meter, I consider it to be a worthwhile investment but if it isn’t within your budget or you won’t use the data there is no need, training effectively and consistently is what makes the difference, the various gadgets and data just make things a bit easier.