Sometimes your heart rate monitor DOES lie to you, also, Philosophic Doubt, yaaaay!

If this seems like a rant, I apologize. The problem with blogging, I am learning, is that in many ways it is like poetry, you strive to illustrate revelations and other large ideas in a small space. But, unlike poetry, you don’t revise, delete, and edit, slavish, for months, before you share.

One of the underlying principles of ABA, all of Science, in fact, is philosophic doubt. What is it? Well, you might be tempted to whittle it down to skepticism, and though a healthy dose of skepticism is a great platform for progress, philosophic doubt reaches a little beyond that.

Without philosophic doubt we’d still think that the world was round, cavemen lived harmony with the dinosaurs, and that smoking does not cause cancer.

People tend to exaggerate, inflate, and generally over generalize things. Interestingly, right in tandem with that, people are constantly over-simplifying things so that they can, I don’t know, make themselves sound smarter (ok, I admit I probably do this ALL THE TIME), to win an argument (also guilty), or because they think they are going to motivate someone, or otherwise make things easier on that person (I try really hard NOT to do this, but still, sometimes, guilty).

Good intentions, however, we all know, can lead you down the wrong path. You know paving the way….

So, where am I going with this. I have a long list of pet peeves when it comes to “fitness professionals” spewing out information that sounds just fine, but is often, in fact. Hogwash.

I will, for now, spare you my rather pretentious, arrogant, and, well, exhaustive, list.

But I will share this annoying bit of dogma with you:

Point of fact, you are not guaranteed to burn 600 calories in a Spin class. I for one, have never burned 600 calories ever, in a spin class. I have been a certified Spin Instructor for almost 7 years, I have never had more than 2 weeks off a Spin bike in all that time, and still never a 600 calorie ride. I am of average height (5’5″), athletic build (132lbs, fairly muscular), and I work hard.  A few times, I have taught a 75 minute class and burned 550-ish but that doesn’t count, I have on many occasions taught 2, 50 minute classes back-to-back, and burned almost 800 calories, this also doesn’t count.

As I have mentioned before, I have a moderate fascination with heart-rate based training, in fact this subject played a major part in my master’s thesis. I don’t often wear my monitor when I run (too much else to focus on), but I wear it for most other workouts.

Heart-rate monitors are actually pretty accurate and reliable. They do, however, have a larger margin of error when you are working out at lower intensities. Which means if you spend a long time warming up, recovering, and in the (totally mythical, by the way) “fat burning zone”, the readout may very likely be inflated.

Additionally, most research done on measuring and monitoring heart rate during exercise (and nearly all other performance related research) seems to be conducted with participants from two very different groups; elite athletes, and individuals who are obese, largely de-conditioned, and or diabetic.

Most of the people being sold the idea that you can walk into a Spin class, hang out for 45-60 minutes and walk out 600 calories poorer, do not belong to the above populations.

I got an email (er, via Facebook), a couple of weeks ago from a friend you used to come to my group exercise classes every week, but has moved out of state. I am going to copy and paste the exchange below because it highlights this discussion. I am copying the text largely unedited, and my response wasn’t premeditated, so surely I am guilty to some degree of simplifying and generalizing the facts. But the underlying points stand.

Enjoy. Learn. Think.

“Heart rate situation/calorie burn

So I have this spin instructor who I like her class but she is the one who told me the wrong info about the calorie counting with the heart rate monitor. The other day I took her 60 min class. I burned just over 600 calories. She came over and asked about the number of calories I burned and I told her and she said there was no way the reading was correct. She said she burned about 750 cal. My heart rate was btwn 160 and 180 for the whole class. What do you think?”

My response

“I applaud you for being suspicious, I wish more people were like you!

I would say that the instructors read-out is wacky, not yours. To burn more than an average of 100calories per 10mins is VERY difficult. In fact I would suggest that yours might be a reading a little high as well.

Let me put it this way, in order for a 150lb person of average fitness to burn 100 calories per 10 minutes they would need to keep their heart rate between 165 and 180bpm, that is very difficult to do!

I would venture to say that the only two types of people who would burn over 700 calories in 60 minutes (mind you, that includes a warm up) is A) Michael Phelps, or someone else of insanely high level of cardiovascular fitness and who has, like, 2% bodyfat and a shit-ton of maturely developed muscle and, B)B) a person who is obese and out of shape, their heart rate would get high and stay high with minimal physical exertion…that would not actually equate to actual calorie burn but the hr monitor would read it as such…also it is unlikely that someone who is obese and out of shape could maintain that high rate for 60 minutes….

So, if your instructor fits into option A, then yes, perhaps she burns that much, but I really suspect not.

I hope my responses aren’t too frank, but inaccurate reporting is why a lot of people give up on their fitness goals, and why they deny the truth when they hear it!

It get annoyed by articles and ad’s that state that this or that workout burns 500 to 1,000 calories, because, honestly that is such an inflation of fact!

In reality, a person should expect to burn between 300 and 450 calories in a good spin class. This is because you have to account for warm up, cool down, and those dips in effort when you have an easy song, an interval recovery, or need to drink some water.

Let’s be clear, though, 300-450 calories burned is a great workout!!!

Overall, I am glad you are finding some classes you like! Just ignore the bull.”

I should add that we’d had previous conversations about the importance of setting the monitor up to meets your needs. Like, make sure it is recording all the time, not just within certain “zones”, to make sure you enter your age, height, and weight….things like that.

So, practice philosophic doubt. If something conflicts with your experience, investigate. Ask questions, even if the information is from an expert.

-AB

 

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