Struggling to get into ‘fat burn’

[Reluctantrunnin]

Hi

First time poster but relatively long time Fitbit user. 

im really struggling to get into fat burn zone doing activities such as brisk walking, hill walking and aerobics.

I’m female, 5ft 8. My RHR is low (between 40-45) - it’s gets very very low at the end of my period (eg this month it was 40 for a few days). Im not an athlete. I’m probably just within a healthy BMI range (at the bigger not smaller end). I do run 3/4 times week (training for a half marathon) plus spinning plus walk at least an hour a day. I can get into fat burn and low cardio when I’m running and spinning. Couple of days ago I walked up a mountain that took 3 hours and I only got into fat burn for 37 mins (so only accumulated 37 active zone mins) - I felt like I was working harder than normal flat walking.

I do get quite a lot of active zone minutes during the week but this is through running etc. if I want to do a rest day or do yoga / stretching / weights - I can’t accumulate any active zone minutes because my heart rate stays well below the threshold for fat burn. I’m finding this quite stressful!

Is this a Fitbit problem (bad tracking of heart rate?), a me problem (weird low heart rate that only gets going when I’m really going for it) or another issue? I’d basically like to be able to ‘reward’ myself for doing other good physical activities like gentle walking and yoga but feel like the fitbits set up isn’t designed to support this. 

[LZeeW]

Hello @Reluctantrunnin and welcome to the Community.  Fitbit's active zone minute thresholds are similar to the CDC guidelines for moderate and vigorous activity.  The CDC guidelines describe moderate activity as you working up a sweat and can speak the words to a song, but not sing it.  Yoga, stretching, weights and gentle walks are unlikely to get you there.  Use the Exercise app with yoga, weights, or the appropriate shortcut to get credit for the activity.  I think that's our only reward.  A rest day is a rest day.  I think your stressing is misguided.

[t.parker]

@Reluctantrunnin you say you're not an athlete but to me, you seem to be quite fit. The fitter you are the harder it's going to be to elevate your heart rate. That's how it works. Assuming that your readings are correct it isn't something unusual that you need a higher level of effort to push your heart a little further. With fitness and improving the cardiovascular system, it comes a time when walking and other low-impact activities do very little for you as they are not demanding enough. Even a brisk walk may become just a "walk in the park". To get AZM you may cheat by changing your zones (by lowering your max HR, however best is to know your real max HR and set its true value) but if your zones are more or less correct and the HR sensor provides mostly accurate data then it may be your fitness just improving (believe me, only handful of people in the world prepare for half-marathons) and simply you need to go harder than last time 🙂

[emili]

Hey there. I don't think it is a "problem" of any sort at all. It is a good thing. You have a healthy heart due to the work you put in. I like to see my active minutes up there too, but I think that is more a wrong story problem I tell myself and you seem to be telling yourself too. Change your mindset to marvel at how efficient your heart is and give yourself a pat on the back for getting it there. Fitbit is just part of the story, don't make it the whole story 🙂 

[charleskn]

I agree with the others that you are probably quite fit and that this is normal. The only other suggestion is to make sure your age or custom max heart rate is correct.

Here is my suggestion for you. I am not a fan of using the fitbit calories burned numbers for dieting, because the numbers are so inaccurate. But the calories burned could work for you in this way. The calories burned during an activity are directly related to your average heat rate ad the duration of the activity, so looking at the caloric burn of your activities could be another way to track your progress/activity.