Charge 2 not recording HR accurately on cold outdoor bike ride?

[nicky.pallas]

Recently I’ve done some outdoor bike rides around 1-2 hours in length, it’s cold outside in New York here around 40-45 Fahrenheit. I’ve noticed my heart rate tracks well for the first ~15 minutes or so (compared to other similar bike rides in warmer weather) and then the HR drops low to a level I know shouldn’t be right.

At my place I know I should be in cardio zone at least, my resting is around 60 and during a normal bike training ride it should be anywhere from 120-170 which records accurately on other bike rides. The clincher is that I’m also wearing a Garmin chest strap which is recording correctly as I anticipate.

Another reference point is that I’ve tested both with my long-sleeves rolled a couple inches up from my wristband to ensure there’s no interference, and also with the sleeves completely over my wrists (not in between Fitbit & skin of course) so I’m sure the long-sleeves and gloves are not the cause of this question.

Does my Fitbit Charge 2 not récord as well in cold weather? Does anyone else notice a similar problem?

[MarreFitbit]

Hey there @nicky.pallas, thanks for stopping by!  Thanks for letting me know what you've tested in order for you to make sure that your Fitbit is tracking your heart rate properly. Nice way to go! 

Well, Charge 2's operating temperature is 14° to 113° F (-10° to 45° C) and non-operating temperature is -4° to 140° F (-20° to 60° C).

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.

As you've mentioned, 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. I know you've tried this already, but I'd like you just to take a look at our recommendations for wear and other tips shared by @SantiFitbit. 

If you're wearing the tracker correctly and the heart rate setting isn't turned off, try changing the setting (either Auto to On or On to Auto) and then syncing your tracker. The change won't take affect until you sync. If heart rate doesn't seem to start tracking correctly, try restarting your tracker and wait at least 60 seconds before checking heart rate again.

[RedEng]

I have absolutely the same issue. I rode 20km this morning at about 10C in about 40-45 minutes on a mountain bike ...and apparently my heart rate didn’t get above 90. As if! Usually my morning ride registers about 300 calories burned. Today it was about 50. Something is seriously off.

[SkinnyLynnie]

I've had the same problem in cold weather.  Yesterday I went for a bike ride.  My heart rate was 87 bpm at the start.  It went up to 109 after two miles.  Then, after four miles, it was only 51 bpm!!!  I didn't feel any different.  I think the cold air blowing on my exposed wrist and FItBit as I rode must have caused the problem.