Why Don’t My Heart Rate and Perceived Effort Match?

Audio Transcript

Sinead: Hey everyone. Coach Sinead here with you to answer your training and racing questions, and help you run smarter and faster.

Today, we have a great question from Rebecca on heart rate and perceived effort.

Rebecca: Hi! I have a question about heart rate. I find that when I run harder efforts like a tempo effort or interval efforts, despite feeling like I’m running at a hard effort based on my breathing and exertion level, I have a hard time getting my heart rate up above 140.

Is this due to an issue with my heart rate monitor or is this normal? Any thoughts you have would be great. Thank you.

Sinead: This is a fantastic question from Rebecca and one that we get pretty often at Runners Connect.

I’ve answered this in another episode, only that person was having the opposite problem; their heart rate was too high for their perceived effort.

I will start by saying there are a lot of variables that go into heart rate and by consequence, there’s a lot of room for error.

First off, you probably are familiar with the training zones for heart rate.

To establish proper training zones, an athlete must first determine their maximum heart rate or their MHR.

Unfortunately, a lot of runners use the simple heart rate formula for that and there’s a good chance you’re probably familiar with the 220 minus your age formula.

Unfortunately, this formula has a very high degree of error and so to get an accurate measure of your maximum heart rate, you would need to do a graded exercise test.

This is a little bit difficult because finding a facility to accommodate this type of testing is difficult. They’re few and far between.

One tip I will give you, if you really want to get a graded exercise test done to determine your maximum heart rate, is find an exercise science program at a local university.

Usually they are looking for test subjects and if you don’t mind being a guinea pig, they might allow you to get your maximum heart rate tested, while they conduct their own little study.

You want to try that out, maybe contact a local university, but for those of you that don’t have access to a facility as most of us don’t, this is where I would suggest basing your training, mostly on pace perceived effort and feel.

This is because, like I said earlier, there are so many different variables that come together to affect heart rate, and your level of fitness is not the only thing that affects heart rate.

A few things that affect your heart rate and make it so that it doesn’t necessarily match your perceived effort are sleep, stress and dehydration.

For Rebecca, these don’t really apply to you because your heart rate is lower than your perceived effort, so I will get into it why that might be in a bit here.

As for these other variables, obviously these three are pretty common and they can have a pretty drastic effect on your heart rate readings.

The first one was sleep and many studies have concluded that a lack of sleep will actually elevate your heart rate five to 10 beats per minute.

This might not seem like a huge change, but coupled with the other two variables I’ll talk about, lack of sleep can cause you to train at a heart rate level that is below your optimal training zone.

Naturally this could really throw a wrench in your training and inhibit you from really hitting the paces that are correct for your race goals.

Another thing to keep in mind is that you do have a lower heart rate in the morning than you do at night.

This is natural for everybody and for you Rebecca, this could be playing a role in why your heart rate seems low even when you are exerting yourself.

If you’re running in the morning, you’re heart rate is going to naturally be a little bit lower and it can also fluctuate from day to day. It can be a bit unpredictable sometimes.

Another variable that affects heart rate is stress and we all know that this is something that we can’t avoid in our lives.

We have good and bad stresses within any given day and so stress has a pretty big impact on heart rate.

One study in particular showed that workplace stress can raise heart rate by four to six beats per minute, so again this doesn’t really apply to you Rebecca, but I want to talk about all the variables that come to play when it comes to impacting heart rate.

Another one is the conditions in which you’re running.

If you’re running in hot conditions, your heart rate will increase as your body works to cool itself down.

This probably comes as no shocker to those of us who are currently training in the hotter climates and feel as though we are working harder than normal.

That’s why they call humidity and heat “the poor man’s altitude.” It means that there is less available blood and oxygen for your working muscles and by consequence, your heart has to work harder to maintain the same pace and effort during your run.

What’s funny is that the opposite is true for colder temperatures.

Your heart rate will actually decrease in response to training in cold environments. Rebecca, I’m not sure where you’re located, but I kind of doubt that it’s particularly cold for you right now, if you are anywhere in the US.

That’s probably not the cause of your lowered heart rate, but what could be is what you said and that might be that the device you’re using isn’t picking up a totally accurate reading.

For you Rebecca, if you feel that your perceived effort is way higher than your heart rate at 140 beats per minute, then it could be the device you’re using.

I’m not sure what you’re using, but if it happens to be a GPS watch for instance, there are a lot of variables that leave some room for error with these.

You going to have to keep in mind that the number you see on your watch isn’t always accurate, in fact most of the time it’s not.

I’ve heard quite a few funny stories when it comes to GPS watches and heart rate, and there are a lot of malfunctioning stories.

For instance, one of our users at Runners Connect determined that the heart rate monitor on their watch wasn’t accurate, because the receiver wasn’t transmitting due to the fact that it got two sweaty.

Another one of our users told me that they determined their receiver wasn’t transmitting, because it was too cold outside.

A professional runner once told me that she looked down at her watch one day, while she was doing a tempo run and her heart rate read 250 beats per minute.

I didn’t even know that those devices went up that high. You have to take the numbers you see on the devices with a grain of salt.

I’m not saying that you need to stop using heart rate in your training all together, but you have to remember that there are some drawbacks, when it comes to trying to reference heart rate when determining paces in training.

Heart rate is very specific to every individual despite that 220 minus your age formula that most of us are familiar with, that is not wholly accurate.

The reference ranges use for that formula range from the fittest to fit, to the average Joe that’s doesn’t run a step ever, so you have to remember that those heart rates are like guidelines.

They’re not totally written in ink because again, everyone’s bodies are different.

Again, those averages are taken from a wide array of people and so if you’re not fitting into the average, there’s usually nothing to worry about.

My advice to you and our listeners today would be to focus more on your perceived effort rather than your heart rate.

We’ll say if you are concerned about your heart rate, to go see a doctor and have an EKG done.

This is a simple test that they’ll do for you and it will determine if your heart is functioning normally and give you a little bit of peace of mind, if you need it.

My best guess is that, either your device isn’t functioning completely accurately or it could be that you have optimized your conditioning for long, slower runs and have been doing it long enough that it’s not really pressing your cardiovascular endurance.

In other words, this might just mean that you are very fit and it takes you a little bit more to get your heart rate up to upwards 170 beats per minute.

Whatever the case may be, I don’t think there’s anything to worry about here.

Like I said earlier, it might just be a false reading on your device if you are running in hot conditions and you’re sweating a lot.

That can have an effect on the reading on your device so again, take these numbers with a grain of salt.

I would suggest again, that you make sure you are putting more emphasis on your perceived effort over your heart rate, especially in the summer when conditions are less than ideal.

It’s always best to listen to your body and focus on your perceived effort and your exertion level.

This will ensure that you are getting the work in. In the summer sometimes, it’s really hard to hit the paces you’re trying to hit, because your body is working so much harder to do so.

At Runners Connect, we don’t really design training around heart rate, because there are so many different variables that go into these readings.

If it’s not 95% correct all of the time, then we’re not going to use that data, so this doesn’t mean that you should never use heart rate or that we think it’s a terrible idea.

It’s just that we think it’s more important to develop your internal sense of effort and pace, rather than have to use your watch for reference all the time.

If you use a heart rate monitor like Rebecca, you don’t have to stop; just make sure that you keep these caveats in mind.

Rebecca, thank you so much for submitting that question. It’s a great question that we get very often at Runners Connect. I hope what I’ve said has helped you and our other listeners today.

If you have a question on training, racing or nutrition, and you would like one of our coaches to answer in an upcoming episode, you can submit it at runnersconnect.net/daily.

We would love to hear from you and help in any way we can.

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