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.
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/pace 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 but at a lower heart rate.
Training to heart rate is more complex than training to pace, but it can be a useful measure if used correctly.
Cons on Training to Heart Rate
Inaccuracy
Firstly, most wrist-based HR data is inaccurate. Whilst it can be a good indicator of your resting 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. This also applies to our HR zones, which sets our training zones. You could have two people who are the same age, same gender and have the same 5k PB, but one person might have a higher easy run HR zone than the other.
Pros on Training to Heart Rate
Stressed out about pacing
If you are on holiday and it is hot, up in the mountains at high altitude, or in a hilly area and you can't find somewhere flat to do session, then training to pace can be quite stressful. When the conditions are not optimal and you know hitting the pace will be tough (or impossible!), then training to HR is a great to way to get in the work and know you are training at the right effort.
Control the effort
You've got a dream pace you want to hit for your upcoming race in 12 weeks and you are determined to hit that in training, but in reality, your fitness isn't there yet. Do you hammer it anyway and push to your max to get there? Or do you ease it back to work in the right zone and trust that over the next 12 weeks you'll get there? The latter is the right answer! If we push too hard too often in training, then this increases our chance of injury. By using HR, you can be confident that you are working in the right zone, not getting carried away and track your fitness over time by seeing your pace improve for the same HR.
Good indicator of illness
This only applies if you track your resting HR over time too, but if you know your HR zones and typical trends, then changes (usually an increase!) in HR are an indicator you are under the weather. This is beneficial for tailoring your training to ensure you are not pushing through when you should be resting!
How to train using heart rate
To train with heart rate, start by identifying your heart rate zones. The most accurate way to do this is through a VO2 Max test, but we don't all have access to this so here are two other options.
The most simple, but least accurate, way is 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 only a field test if you are healthy, uninjured and 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:
Warm up for 15-20 minutes
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.
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.
Run up the hill at a maximum effort for 45 seconds to a minute. You should achieve your maximum heart rate.
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 during intervals.
Most races will be run in Zone 3-5 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:
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.
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
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.
At Runna we think HR is useful but we recommend primarily running to pace and using HR data as a secondary measure. Pace gives us the confidence we need for race day and the more we get used to running at a certain pace, the more conditioned our body is to that pace come race day. However, HR is great if the conditions are not optimal for the session on your plan, to check you are working in the right zone and not overdoing it, and to track your health over time. BUT it is key that you wear a chest or arm strap during your run sessions! Happy training.