Why I Don’t Use a Heart Rate Monitor


Recently, I have received some questions about HRM’s and what my thoughts were on them. I don’t wear one and I never have. Some gyms use them and even have their clients wear them so they can show their clients’ heart rate on a big screen to determine if they are pushing hard enough. While knowing your heart rate during certain exercises is helpful for some people including heart patients and competitive athletes, it isn’t necessary for all.

The average person who wears a HRM (not for the reasons listed above) most likely wants to track their heart rate during an exercise routine to make sure they can burn as many calories as possible. However, while your heart rate monitor may be accurate for certain cardio or aerobic exercises performed, the relationship between heart rate and calorie expenditure is not the same during strength training as during cardio exercise, which is what the heart rate monitor's estimate is based on.

Dr. Stacy D. Hunter states this in an article she wrote that I felt was precise and worth sharing:

“HR monitors provide estimations of calories burned based on the relationship between heart rate and oxygen consumption. When more oxygen is consumed, more calories are burned and heart rate increases. This relationship is a key factor in the estimation of caloric expenditure from heart rate. The estimation of calories burned from heart rate is based on the heart rate and oxygen consumption responses to endurance or aerobic exercises. While you can use a caloric monitor while weightlifting, you aren't likely to get an accurate result due to the mechanics of this kind of workout.”

Ok, so we see there may be some flaws when it comes to calculating calories in strength training, but let’s look at just the accuracy of simply reading your heart rate. During any sort of cardio exercise (steady state running etc.), studies show that the HRM’s tend to be fairly accurate. However, after extensive research there is currently little to no evidence on how accurate heart rate monitors are when weight training. In fact, it has been recently reported that Fitbit, the popular brand of fitness trackers (wrist-based monitors), is facing a class-action lawsuit over faulty heart rate monitor results. Regardless of the lawsuit, they state on their website the following could cause inaccurate readings:

1. Do not wear your tracker too tight; a tight band restricts blood flow, potentially affecting the heart rate signal. That being said, the tracker should also be slightly tighter (snug but not constricting) during exercise than during all-day wear.

2. With high-intensity interval training, P90X, boxing, or other activities where your wrist is moving vigorously and non-rhythmically, the movement may prevent the sensor from finding an accurate heart rate. Similarly, with exercises such as weight lifting or rowing, your wrist muscles may flex in such a way that the band tightens and loosens during exercise. Try relaxing your wrist and staying still briefly (about 10 seconds), after which you should see an accurate heart rate reading.

Polar, a popular brand for chest strap monitors indicates these following factors that could cause an inaccurate reading on their website:

Abnormal Heart Rate Readings During Exercise 1. Heart rate view during exercise (HR / HR%) 2. Poor contact between the skin and the electrodes of the heart rate sensor 3. Wear and tear of the heart rate sensor 4. Electromagnetic disturbance 5. The distance between the training computer and the heart rate sensor with GymLink transmission is too long 6. Signals from more than one Polar heart rate sensor with GymLink transmission 7. Static electricity, technical sportswear and special conditions


8. Arrhythmia


9. Battery of the heart rate sensor is getting empty

Again, when you are running or doing a steady state cardio exercise, there is less room for error, however with weight training or HIIT when there are more body movements, room for error increases. You get the idea.

Furthermore, I believe we all know when we are pushing hard during a workout and when we aren’t. At Capstone Fitness in La Quinta, we evaluate all of our clients by many different aspects to determine the intensity of the workout. It's not necessary to rely on an electronic device. We also believe in taking out as many variables as possible when it comes to achieving your fitness goals. In fact, with our nutrition program and CUT by Capstone program, we don’t even have clients log their estimated calories burned (typically taken from HR monitors) in exercise because if that is inaccurate it will in turn make their nutrition counts inaccurate, and it could sabotage their goals.

In short, if you use a heart rate monitor, remember don’t solely rely on it. If it helps motivate you, keep on using it! More accurate ways to measure progress can be found in the mirror, in pictures, in strength tests etc. If you need to know your heart rate, it is very simple to check it manually.

Remember, weight training changes your body, cardio can change your size. 😊

To good health today and always!

Christina

Additional reading:

http://livehealthy.chron.com/can-heart-rate-monitors-measure-calories-weight-lifting-4910.html

http://berkeleysciencereview.com/fit-fitbit/

https://www.technologyreview.com/s/538416/the-struggle-for-accurate-measurements-on-your-wrist/

http://www.wired.com/2012/08/fitness-trackers/

http://www.edn.com/electronics-blogs/sensor-ee-perception/4441200/4-reasons-Fitbit-is-being-sued-for-inaccurate-heart-rate-monitors

About:

Capstone Fitness is an exclusive personal training studio based in La Quinta, CA, serving Indio, Palm Desert, Coachella, Bermuda Dunes, and surrounding cities. We offer training in a clean, comfortable and friendly atmosphere.


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