Heart rate very inaccurate during interval training

[Emilyv404]

Hey everyone- wondering if I’m doing something wrong and if anyone has noticed this problem. I just got my Fitbit inspire HR yesterday, and this morning I ran a couple miles to the gym. Given past heart rate monitoring, the data for the run was pretty accurate. However, at the gym I did about 30 minutes of HIIT training. My Fitbit never registered a HR of above 120. It was around 100 the whole time. I took my heart rate multiple times, and it was between 150-180. Is there anything I can do to fix this? It’s super frustrating because a big reason I purchased this was for exercise tracking, and it seems it doesn’t even work correctly. Thanks!

[YojanaFitbit · Accepted solution]

Hey there @Emilyv404, thanks for reaching out the Forums. Welcome! 

I'm glad to see that you are using the Inspire HR model to track your workouts at the gym. Thanks for sharing those details on your post about your HR readings. I'd like to mention that your heart rate may be affected by any a number of factors at any given moment. Movement, temperature, humidity, stress level, physical body position, caffeine intake, and medication use are just a few things that can affect your heart rate. Different medical conditions and medications can impact your heart rate as well.

What is the higher BPM that you have reached while working out? Are you currently taking medications?

I'd like to mention that when your heart beats, your capillaries expand and contract based on blood volume changes. PurePulse LED lights on your device reflect onto the skin to detect blood volume changes and finely tuned algorithms are applied to measure heart rate automatically and continuously. The heart-rate icon you see on the display tells you if you're in 1 of 3 heart-rate zones. You will find more details about it here.

Your tracker can have difficulty finding a signal, typically due to the tracker's fit. For example, wearing your band tightly may constrict blood flow in your wrist and affect the signal. We recommend experimenting with how high you place the tracker on your wrist. When you're not exercising, wearing the tracker just above the wrist bone as you would a watch typically works fine. However, moving the tracker up a couple inches can be helpful during high-intensity exercises or exercises that cause you to bend your wrist frequently. If you haven't already done so, please review our recommendations for wear and other tips shared by @SantiFitbit. 

If you're wearing the tracker correctly but you feel it is not the correct readings, try restarting your Inspire HR and keep an eye to future readings.

Give this a go and let me know how it goes! 

[murphyX]

HI, just jumping on this post from ages ago! I have just purchased an inspire HR and I have worked out how to now change the type of exercise-i do Hiit which was not on it-but I chose Tabata Workout?  This morning it seemed to register everything BUT Im not sure the calories burned is right?

Im wondering if my set up is right? So it says that I did a workout for 34 mins (I did it for 45 mins? But maybe it only registers the actual high intense times?) It says that I was working with 71% Fat burn and my heart rate was average 115 bpm. BUT it says that I only burned 120 calories??

Whereas my friends said she had burned 420 calories?? 

Can you shed some light on this or help?

Thank you!

[DawnKeck]

I have the same problem.  I know what I feel like at 120, 150, and 170.  I did HIIT today, and sometimes my Fitbit registered my heart rate at 170 but sometimes at 120, when I KNOW it should’ve read 170.  I only have this problem during intense exercise like HIIT.

[AndyRoo2020]

Hi there,

I got the new sense yesterday and have the exact same issue, doing HIIT training with heart rate 160-180 it seemed to sit around 120 the whole time. I will continue try and move it up my wrist as advised but if that dosent fix the issue what else can be looked at? Cheers.