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Pros and Cons of Heart Rate Monitors.

Heart rate monitors are not an accurate way to measure your heart rate or intensity during your Burn360 workouts, which are based on HIIT (High-Intensity Interval Training). I don't use one and in this article, I'll explain why.

Susan Ohtake

Certified Personal Trainer

I get this question a lot and you might be surprised by my answer...

Heart rate monitors are not an accurate way to measure your heart rate or intensity during your Burn360 workouts, which are based on HIIT (High-Intensity Interval Training). I don't use one and in this article, I'll explain why.

The problem with heart rate monitors & HIIT

Heart rate monitors are good for some activities (I cover that below), but they are NOT good at good at tracking your max heart rate. Even the companies that make them will usually disclose this.

So why are heart rate monitors notoriously inaccurate at tracking HIIT workouts? The answer is this: There is too much fluctuation with your heart rate during HIIT. Your heart rate is constantly going up and coming back down, over and over again for short periods of time, and the monitor simply cannot track it accurately.

Gauge your intensity using RPE

Instead of focusing on your heart rate, I want you to focus on your Rate of Perceived Exertion (RPE). RPE is just a fancy way of saying how hard you feel like your body is working. You are going to focus on how you feel and get in tune with your body. Intensity is subjective and can vary depending on how you feel from day to day.

How to you figure out your RPE

It's simple. I use an "out of 10" scale to measure intensity.

1 is super easy, 10 is super hard.

If your maximum intensity level is a full out sprint (i.e. as fast as you can go for 10 seconds), then that's your 10/10 (max) effort level. Start scaling down from there to determine your individual effort level.

Like this...

2/10 (almost as easy as you can go)
5/10 (somewhere in the middle)
10/10 (AS HARD AS POSSIBLE! 🔥💦)

It may take a few workouts before you discover the right amount of intensity for your individual fitness level, but have no fear! You'll be surprised at how quickly you'll adapt and get in tune with your body.

The RPE Advantage

A major advantage of using Rate of Perceived Exertion (RPE) to measure your intensity is that RPE is subjective. It’s completely based on how you feel while you’re working out.

More objective measurements of intensity like how fast you’re going or even what your heart rate is don’t take into account factors like: How well you slept last night or how stressed out you’re feeling today.

What about the "fat-burning zone" and monitoring calories burned?

You might be used to using a heart rate monitor to know if you’re in the “fat-burning” zone. However, the "fat burning zone" is for low to moderate activity. HIIT works differently and your heart rate will not be in the "fat burning zone" while you workout.

HIIT workouts are effective at getting you great results so fast because they trigger the "afterburn" where your body continues to burn calories for up to 48 hours after your workout is over. (The technical term for this is EPOC - Excess Post-Exercise Oxygen Consumption).

This is why you shouldn't use a "calories burned" monitor either. It's simply not accurate for this style of working out.

What are heart rate monitors good for?

Despite not being accurate for HIIT, heart rate monitors are useful in other scenarios:

They are good for tracking sleep and recovery. For example if your heart rate is high during the day, then you know your body isn’t recovering enough.
Active recovery is another great use for heart rate monitoring since you want to make sure you're not overdoing it.
Monitoring is good for endurance athletes, and many do heart rate training. Endurance athletes have much less drastic fluctuation in heart rate, allowing for accurate tracking.
Monitors with a chest strap are good for low to moderate intensity cardio.