Heart rate reported during exercise is just...impossible

[inspired_laz]

Hi there!

I've had my Inspire 3 for about five days. I've been using it to track exercise workouts at the gym using the Activity feature: treadmill and weight lifting. Unfortunately, the heart rates it's reporting are simply...impossible! For example, a brisk walk on the treadmill at 3.5 miles per hour (which hardly taxes me) will start to show my heart rate rising first into 'fat burning' range and then 'cardio' and then 'peak' in the space of less than 30 seconds, all the while my exertion level is the same. And if I come to a complete stop, the heart rate keeps rising, all the way to 'Peak' (150 bpm). And this same thing happens during weight lifting sessions (hardly aerobic). If I exit the activity, the rate shown on the main time display looks more reasonable (still on the high side) but as soon as I restart the Activity, the rate soars even if I'm not doing anything.

I've already tried several different ways of wearing it on my wrist (loose, tight, higher/lower) and nothing seems to remedy this. Might the sensor be defective?

Thanks in advance!

inspired_laz

[alexthecat]

@inspired_laz I've found that the motion or position of my wrist during some type of exercise interferes with my Fitbit reading my heart rate correctly. The device keeps sliding around and that interferes with heart rate detection. My solution is to push the Fitbit higher up my wrist and use an adjustable knotwork bracelet to keep it there. It looks like this. 

I've also used a bandana or a sweatband in the same way. 

[inspired_laz]

Heya...thanks for the reply and the suggestion. I'll give it a whirl.

laz

[alexthecat]

@inspired_laz great! Let me know how it goes. 

[inspired_laz]

As suggested, I donned a nice sweat band and located the Fitbit further up my wrist. Things seemed OK during my treadmill session but once I started weights, things went awry, same as before. A few minutes in, the Fitbit started showing my heart rate going rapidly up, even though I was resting at the time. It climbed up into cardio, peaking at 144. I can attest, my heart could not have been beating any faster than high 80s at this point. This happened two more times during the workout. I am now wondering if there's simply a bug in the Fitbit programming and some particular movement I make (bending my wrists?) that sets it off, And once it starts it continues to read elevated for at least a minute or so before coming back down. Greatly lessens the value of any data being collected during the workout.

Thanks for the suggestion anyway, @alexthecat.

inspired_laz

[alexthecat]

@inspired_laz have you tried restarting your device? Sometimes that helps when I encounter unexpected behavior. 

[inspired_laz]

Thanks. I've tried restarting several times when this has happened. But eventually the heart rate spike returns.

I've now seen the behavior while just standing around, just observing the main display, not in a workout. It's either a problem with the sensor itself or a bug in the software. ::shrug:: It's brand new so my inclination would be to get an RMA and have it replaced.

Does support monitor these forums?

inspired_laz

[alexthecat]

@inspired_laz no, Customer Support does not read the forums. You'll need to contact them directly. 

[inspired_laz · Accepted solution]

OK...some more tinkering with this and some success to report...

Before working out I moved the Fitbit as far up my forearm as possible, limited by the length of the rubber strap: it was buckled on the last possible hole. I'd say it was about four inches above my wrist. I then slid a sweat band on and positioned it just below the Fitbit to keep it snugged and prevent slipping. I then did a treadmill workout followed by a weight workout, each about 20 to 25 minutes long. The reported heart rate reported during both workouts seemed a lot more reasonable.

The treadmill workout was only moderately intense (3.5 to 4 mph) and reported heart rate peaked around 110 to 115 bpm, which was probably a bit higher than it actually was. But at least there were no "runaways" i.e. reported bpm never rose to cardio and then peak). The Fitbit also behaved much more reasonably during the weight workout and while there were no runaways, it did seem like it was reporting much higher than actual bpm a couple of times. However, if I rested and briefly let my arm hang at my side, the reported rate went down quickly.

So...while I can't say the Fitbit heart monitor is the most reliable measure of heart rate during exercise, I am able to coax it to behave better by modifying how I wear it. Possibly with a longer strap I could move it even further up my forearm and obtain even better results.