Why Doesn’t My Heart Rate Reflect My Perceived Effort

Audio Transcript

Today’s question is on how the heart rate and perceived exertion correlate and should be used in training.

The question reads, “I am curious about why my heart rate doesn’t reflect my level of perceived exertion. For example, I run at what I think is a very easy pace, and when I look at my heart rate data after the run, it shows that I have beentraining too hard, more like temple range. Hard running sends it through the roof. My resting heart rate is higher than average for my age.

My question is, should I continue training according to perceived exertion, or should I pay more attention to my heart rate and thus end up walking for most of my runs to keep my heart rate from escalating out of the easy range? I have been running for a few years and over that time, my heart rate hasn’t changed much.”

Right off the bat, I want to say that while heart rate monitors can keep you in the right training zones, prevent over training, and help monitor progress, training using a heart rate monitor is typically less accurate and more problematic than simply training by pace and feels.

You want to focus more on perceived exertion rather than focus on the numbers on your heart rate monitor.

This is because there are so many different variables that come together to affect heart rate and your level of fitness isn’t 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 exertion are sleep, stress, and dehydration.

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

Your heart rate won’t always fit into the designated training zones despite how fit you are.

The first of these variables, again, is sleep.

Many studies have concluded that a lack of sleep will actually elevate your heartrate 5 to 10 beats per minute.

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

Naturally, this could throw things off and inhibit you from training correctly to reach your race goals.

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

That doesn’t even take into account that your heart rate can vary by two to four beats per minute, from one to the next, without changes to fitness or fatigue.

It can be a little bit unpredictable sometimes. You have to take into consideration that there will be a little bit of fluctuation from day to day, and even more so from morning to night.

Another variable that affects heart rate is,stress and we all know that this is something that we cannot avoid in our lives.

There is good stress and bad stress. Within any given day, there is some sort of stress going on.

Stress has a pretty big impact on heart rate. One study, in particular, showed that work place stress raised heart rates by four to six beats per minute.

This is an important statistic for runners who train after work, because at that point, you have stress from your work day influencing your heart rate. Bear in mind that you’re also training in the afternoon.

Naturally, your heart rate is going to be a little bit higher than it would have been in the morning.

That’s another thing to keep in mind, that while running is obviously a great way to reduce the effects of stress, the elevated heart rates you experience, while in a stressful state, will actually change the heart rates at which you should be running.

Another variable that could influence your heart rate and make it fluctuate from day to day is the weather.

During hot days, your heart rate will increase as your body works to cool itself down. This is no shocker to those of us who have run in those hotter climates particularly during the summer.

In hot and humid conditions, blood is sent to the skin to aide in the cooling process.

This means there is less available blood and oxygen for your working muscles. Obviously, what that means for your body is that your heart has to work harder to maintain the same pace and effort during your run.

This should come as no surprise to those of us who have run in those hotter climates, because you’re usually working at a much harder effort to hit the same pace or even a slower pace.

What’s funny is the opposite is true for colder temperatures. A heart rate will decrease in response to training in cold environments.

Researchersposit that training in cold temperatures results in an increase in stroke volume and thus a higher V02 Max which will lower the perceived effort and reduce your heart rate.

This is why, for a marathon, the optimal temperature is about 40 degrees Fahrenheit rather than 95 degrees Fahrenheit. The colder temperature slightly decreases your heart rate.

Again, what this does is it helps to lower your perceived exertion.That’s naturally why most runners prefer running in cooler temperatures rather than hotter temperatures.

The last significant variable I’ll talk about is dehydration. Dehydration has a profound effect on heart rate.

In one study, researchers found that cyclists who exercised in a dehydrated state exhibited heart rate readings that were 5 to 7.5% higher than normal.

That is a pretty massive change in heart rate that can obviously also drastically influence your heart rate training zones.

Each of the variables I’ve talked about: dehydration, stress, sleep, and weather, all come together to make it easy for you to exercise outside your target heart rate zones on any given day.

I’m not saying that you should throw out your heart rate monitor, but you have to take these variables into consideration when trying to use your heart rate as a reference in training.

Something else that you have to keep in mind is that heart rate training zones are often wrong. Another inherent drawback to heart rate training is simply how difficult it is to establish your max heart rate and accurate training zones.

Although we, at Runners Connect, have a calculator to help find your max heart rate, the problem is that heart rate calculators are based on an average.If you’re not in that average, that’s where things can, kind of, be thrown off.

Not only that, but maximum heart rate isn’t always the best predictor of training zones. How this works is that, in order to establish proper training zones, an athletemust first determine their maximum heart rate or MHR. What happens here is a majority of runners typically use a simple heart rate formula and that is usually 220 minus your age.

If that rings a bell, you’re not alone. A lot of people use that.

To get an accurate measure of your maximum heart rate, you need to partake in an actual graded exercise test. This is because a simple formula of 220 minus your age has a high degree of error.

For a complete accuracy in determining your max heart rate, you have togo and get a graded exercise test done, but unfortunately, locating a facility that can accommodate this type of testing isn’t easily found.

I will say that a lot of universities will do this for you, and a lot of exercise science programs will happily do this kind of test for you, because they often need subjects for research purposes. That could be a good option if you don’t mind being a lab rat.

You do have to keep in mind also that these graded exercise tests aren’t going to be appropriate for a beginner runner who can’t handle such a stressful workout.

These graded exercise tests can be a bit strenuous. If you are going to do one, you have to keep in mind that you don’t want to do one anywhere near a race or anywhere near a hard workout.

The unfortunate reality is that you haven’t gotten near a max heart rate from one of these graded exercise tests, and you’ve instead determined it from a heart rate calculator. The room for error will be too high to call it completely accurate.

Another thing to note is that, unfortunately, maximum heart rate is not really the ideal way to measure the body’s response to exercise.

The ideal way is blood lactate levels. Research demonstrates that there is no predictable relationship between heart rate and lactate threshold, which is kind of a shocker to me.

I don’t know about you. Lactate thresholds tendto occur at around 90% of maximum heart rate in well trained runners. It can occur at 50% of max heart rate in beginners.

The bottom line here is that optimal training zones could be far outside what traditional heart rate training advocates suggest.

This is because these training zones are determined based off of an average. When you have beginners up to experienced runners, you can get an average that most likely won’t suit you and your training needs.

One more thing that you have to be a little bit weary of when you’re determining your heart rate,is the heart rate monitor you’re using.

If you are using your GPS watch, for instance, to determine your heart rate, there are a lot of variables that leave some room for error here.

You have to keep in mind that the number you see on your watch isn’t always accurate.

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

For instance, one of my friends determined that their heart rate monitor on their watch wasn’t accurate because the receiver wasn’t transmitting due to the fact that it got too sweaty.

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

There are a lot of different variables that can cause the GPS watch to lose accuracy. A professional runner once told me that she looked down at her watch one day and her heart rate read 250 beats per minute.

Obviously, that could not have been correct. That was just completely ridiculous. You have to keep into consideration that when you’re using your GPS as a heart rate monitor, there is a lot of room for inaccuracy there.

I’m not saying that you need to stop using heart rate in your training. I just want to make sure that you keep in mind that there a few drawbacks when it comes to trying to reference heart rate when determining paces in training.

Again, there are so many variables that influence heart rate that perceived exertion is a far better way to determine the paces you run, rather than trying to hit designated heart rate zones.

For instance, our questioner said that even for an easy day, she would have to start walking to hit her easy heart rate zone.

This is not how it should be. If you feel as though you are running easy, then that is how you should be running.

You shouldn’t change your pace simply because of what your heart rate monitor says. I have a friend who’s a professional runner. She runs for Sketchers and has ran a 233 marathon. She has an unusually high heart rate even at rest.

I know, for instance, our questioner said that her heart rate is usually high even in the rest state. The same is true for this marathoner. Even when she’s going for an easy run, her heart rate would not suggest that she is running easy.

Heart rate is very specific to every individual. That’s why the averages that are used in a lot of heart rate calculators are typically pretty inaccurate because everyone is wired a little bit different.

I will say that in my friend’s case and this is Esther Atkins – some of you may know her. Sheis a professional runner for Sketchers, but Esther determined that she has a heart mummer and she believes that this might be why her heart rate is slightly higher than the average persons.

Obviously, this doesn’t affect her running seeing that she’s a very accomplished athlete.

It can be good, if you’re concerned about your heart rate, to go and see a doctor and they’ll have you do an EKG. This is a simple test that they’ll do for you.

It determines if your heart is functioning normally and it can give you a little bit of peace of mind, if that’s what you’re looking for.

If your heart rate is a little bit higher than average for your age, this is nothing to worry about. Those averages are taken from a wide array of people.

If you’re not fitting into the average, that’s nothing to worry about. Again, my advice to you and my advice to our listeners today,would be to focus more of your attention on your perceived exertion rather than your heart rate.

Between your perceived exertion and the feedback you get from your performances, whether they’d be workouts or races, you’ll be able to better determine the paces that you need to hit on easy days, workout days, and long run days to achieve the goal race you’re looking for.

I really enjoyed answering that question. I hope I’ve given you guys some helpful information that you can use in your training.

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