Active Zone Minutes on Charge 6

[JonInHen]

I recently changed from Charge 4 to Charge 6.  Since I did, I cannot exercise hard enough or long enough to register any significant active zone minutes.  On the Charge 4 I was easily getting 30 plus minutes daily.  With the Charge 6, I am only getting about 9 minutes daily.  Once I noticed it, I started working much harder much longer with little effect.  To try to get more zone minutes, I have drastically increased my walking times and intensity.  Today i logged 20,000 steps going as fast as I could.  No improvement - still got only 9 zone minutes today.. I very rarely can get above the moderate activity heart rate with the Charge 6.  I usually was at peak level about 20% of the time with the Charge 4.  I have yet to ever hit peak level using Charge 6.  Any suggestions or fixes?  I am 72 with AFib and a little reluctant to exercise any harder than I am now.  Any help/suggestions appreciated.

[Bill_209]

You will find dozens of similar posts from other people about zone minute observations made after the last device 210.26 firmware update, as well as at least one of the last several App software updates.

Something about the 210.26 firmware using a new heart rate algorithm and then zone minute calculations being changed somewhere along the way as well.

[Bookwyrm4802]

Is it possible your watch isn't tight enough on your wrist? Just a thought?

[LZeeW · Accepted solution]

@JonInHen   To clarify, the Charge 6 uses a different heart rate algorithm than the Charge 4.  Fitbit claims this new algorithm is more accurate at faster heart rates.  You must think of them as completely different devices.  The thresholds for moderate, vigorous, and peak did not change.

My husband was put on a beta blocker when he developed Afib.  His doctor mentioned other medications, but they all have the same goal, to prevent the fast heart rates that can happen with Afib.  They also make it hard to raise your heart rate when exercising.  You can try the following adjustment.  You set a Custom Maximum Heart Rate.  This is the path:

• Tap on your profile picture in the upper right of your app
• Tap on Fitbit settings
• Tap on Heart rate
• Tap on Heart rate zones
• Toggle Custom Max Heart rate on

You will see your max heart rate bases on the 220 - age equation.  Try lowering it by at least 10 bpm.  This will adjust your heart rate zones.  It might take some trial and error to get ranges that work for you.

When my husband first developed Afib, he was in Afib some of the time, but not all of the time.  He could tell the difference, because his exercise tolerance changed.  Based on his experience and what I know about Fitbit accuracy, I think your Charge 4 overestimated your heart rate.  People in Afib tend to get lightheaded and short of breath at 'peak' heart rates.

[JonInHen]

Good question - and answer is I do not know. I had already thought of that
and tried it with the strap at all various tightness. Did not see any
difference at any strap setting. No matter where I put the strap, I cannot
get beyond the light activity heart rate. But it still could be the strap
tightness. Will keep experimenting with it. Thanks

[Bill_209]

If you have a continuous heart rate curve, with no breaks, then chances are your wrist strap placement is just fine.

[JonInHen]

Thank you.  Using a Custom Max Heart Rate seems to be the solution.  I just did a pretty good aerobic workout for 20 minutes and got into the vigorous range for 10 minutes of it and got 13 active minutes.   Yesterday doing same workout, I could not get beyond the light range and got zero active minutes.  It may not be 100% accurate, but getting some active minutes instead of zero day after day no matter how long/hard I worked is better.  Now I got a measuring stick to work with instead of zeroes.  Much thanks. Happy New Year!

[JonInHen]

Thank you!!  I 100% will give this a try.  Sent from my T-Mobile 5G Device

[BuddhaDave]

Try the Best Answer above from LZeeW - lowering and adjusting your Max heart rate will result in getting Zone Minutes on Charge 6.

[BuddhaDave]

Thanks for that information, the fix seems to work for me.  Lowering my Max Heart Rate resulted in Zone Minutes showing up on my Charge 6.

[9v9z9f]

Why does my active zone minutes go up sometimes when I'm doing nothing much, like lying down on the settee or something? Like today.  Can someone tell me why?

[RiekoC]

Hello @9v9z9f 

According to the provided pictures, they show that your heart rate was in the Vigorous and Peak zones. Did your heart rate graph show the same spikes?

FWIW, I've seen where my heart rate spikes into the upper ranges when I'm not actively working out, resulting in AZM and Cardio Load points. This often happens when I'm anxious or excited about something. 

[9v9z9f]

Yes I think it did show the same spike's Vigorous and Peak Zones.  Any suggestions on what to do next time it does it when not doing much? Can anyone tell me?

[RiekoC]

Hello @9v9z9f 

Personally, I would continue to monitor your heart rate spikes that happen when you're not doing much as well as what's going on at the time.

For me, I know that when I'm very excited or anxious, I see the spikes. Since I know the cause, I don't worry about them, but do recognize them and keep monitoring for any additional unusual activity.

If you continue to see these kinds of spikes without explanation, consider confirming the spikes by doing a manual check of your heart rate or get another device, like a pulse oximeter, to confirm.  Pulse oximeters are usually inexpensive and also take heart rate readings. Then, if you get confirmation of continued spikes, it might be worth discussing them with your healthcare provider.