Activity Minutes vs. Calories Burned

[RodneyJ]

Hi! I use a Fitbit Versa 4 and enjoy it. I'm really interested in Calories Burned and Activity Minutes on the app and the watch. However, I noticed during my walks to school(taking my daughter to school), the walks don't show up at all in "Active" Minutes. In fact, I could spend 2 hours walking and it wouldn't show any Active Minutes recorded...because my heart rate really wouldn't be too elevated. My resting heart rate is 54.....and when I walk, it's up to 100. But my Active Minutes don't start recording until my heart rate hits 105+. It seems like, although it's nice to look at Active Minutes on the app/watch, calories burned seem to be a better indicator of total activity. Because, as I'm walking, my calorie burn is increasing.....even though my heart rate isn't up over 105. But my heart rate has almost doubled from my resting heart rate while I'm walking to school. I noticed the same thing with weight training - my heart rate, overall, is elevated......but it only records Active Minutes when it ramps up past 105 - and most of the time, it's not over 105 during weight training. Isn't overall Calorie Burn a better indicator of activity? I mean, I love the Active Minutes number......but it doesn't seem to "count" everything I do during a typical day......whereas the Calorie count seems to count everything due to the heart rate being higher at certain times(even when it doesn't reach that 105 threshold for me). Do I have this right? Or am I totally wrong with this approach?

[LZeeW]

Hello @RodneyJ and welcome to the Community.  A little clarification.  Your Versa 4 awards Active Zone Minutes, not Active Minutes.  Active Zone Minutes are heart rate based and use your resting heart rate in the equation.  Your heart rate zones are divided into Moderate, Vigorous, and Peak.  You get 1x the number of minutes in the moderate zone and 2x the number of minutes in the vigorous/peak zones.  Fitbit uses CDC recommendations.  The current recommendations are for 150 minutes/wk of moderate aerobic activity or 75/wk minutes of vigorous aerobic activity or a combination of the two.  It also recommends strength training two days a week.  Fitbit's Active Zone Minutes help you meet these activity recommendations.

The CDC uses brisk walking as an example of a moderate activity.  Your weight training is important.  I think it's very hard for anyone to get Active Zone Minutes lifting weights.

CDC: How much physical activity do adults need? 

CDC: Benefits of Physical Activity 

[JohnnyRow]

Adding to what @LZeeW correctly stated, yes calories burned includes everything, but that is not the intent of zone minutes, or active zone minutes (not activity minutes as you were calling them).  The purpose of active zone minutes is to measure the time when your activity is at a higher intensity, which has added health benefits.  If you are hitting a heart rate of 100 when walking, you would probably find that it would reach the required 105+ with little extra effort (probably not when walking your daughter to school), to earn yourself some zone minutes and added health benefits, although of course the difference between 100 and 105 heart rate is not really a magic cut-off point with huge health benefits, but just seeing the numbers can be a motivation.

[RodneyJ]

I guess here's what I'm trying to figure out:

I've been looking at two main numbers on my Fitbit Versa 4........the first is Calories Burned per day......and the second is Active Zone Minutes. It seems to me, if I'm not mistaken, Calories Burned measures pretty much everything. So, if I'm walking my daughter to school...lifting weights....running....cycling....whatever, it measures all of it. If my heart rate is higher, the Calorie Burn is higher per minute. As the intensity goes up - like when you are in "Peak" Activity Zone - the calorie burn actually goes higher than if you're in "Moderate" or "Vigorous" Activity Zones. If I'm walking my daughter to school(30 minutes each way), the Calorie Burn also counts all of that movement even if my heart rate is below 105. So, at the end of the day, the Calorie Burn number counts everything I've done. So......that's great.

But......it seems to me(if I'm not mistaken)......that if I'm concentrating more on Active Zone Minutes.....then my fitness level goes up. So, instead of just looking at Calories Burned, I'm really just concentrating on Active Zone Minutes per day........so trying to increase that number per day is doing "more" to help my fitness level. I'm trying to figure out if that is truly the case. I've had days where my Active Zone Minutes were 150(for the day), but my Calorie Burn was below 4,000 for the day(mostly because I was sitting or doing low heart rate activities the rest of the day). In turn, I've had days where I've burned 5,000+ calories.....but my Active Zone Minutes were below 40......because I was doing a ton of walking(up to 45,000 steps for the day.....at a heart rate lower than 105 for most of it). So......my question becomes......which is more important? The Calorie Burn or the Active Zone Minutes? Right now, I'm averaging 120 Active Zone Minutes per day. I'd like to increase it. But I'm also looking at Calories Burned, thinking maybe that catch-all number is the real one I should be looking at, instead of Active Zone Minutes. I read somewhere - possibly on this forum - that to increase fitness(my primary goal), you should look at the Active Zone number. But I'm wondering if this Calories Burned number is more worthwhile - trying to increase that number, even if some of my Active Zone days are pretty small.

[JohnnyRow]

I hope this amount of exercise has not been just a recent increase, but something you have been building up to for quite a long time. Otherwise if this is just a recent increase so your body is not used to it, I would worry you could be headed for an overuse injury, and hope you are getting your body plenty of rest.

Assuming this has been an on-going routine, this gives me a totally different viewpoint of your situation.  From your first post, I got the idea you were getting barely any zone minutes.  But if you are averaging 120 AZM per day and walking up to 45,000 steps a day, you're way beyond the level of trying to maintain a basic fitness level.  The CDC and American Heart Assn recommend 150 AZM per week and you are nearly doing that in a day, so I'm not sure I'm in a position to be giving you any advice other than not to overdue it to the point of getting injured.

[RodneyJ]

Yes, I understand - thank you so much. No, this isn't new to me....I've spent quite a long time at this activity level....after a very long build-up. Sundays are normally in the 270+ Activity Zone Minutes range......and I normally average around 120+ per day on the other days. I enjoy using my Fitbit, but I'm really trying to concentrate on just that one goal(for simplification)....either Calories Burned or Activity Zone Minutes. I guess....from what I've been reading on other posts across the Net....AZM is really the way to go for overall fitness. And I guess, reading back on my own post, that was my real question.......what was more effective for fitness....AZM or Calories Burned. Others, like myself, have noted that things like walking are rarely recorded in AZM because of the heart rate. One runner noted that when she switched from running to walking, her Calorie Burn stayed the same....even though her AZM was next to nothing.....and she felt her overall fitness had actually decreased(even though Calories Burned remain constant). That was a concern of mine too....what would happen if I just concentrated on Calories Burned? It's a catch-all.....but, like her, I found my AZM could be minimal and my count would still be elevated because of all the steps. In turn, I felt less fit. So, I was just pondering this subject of Calories Burned vs. Active Zone Minutes. Thank you so so much for your help - it is really appreciated - thank you!!

[JohnnyRow]

I guess I would say at most average levels, intensity, with adequate rest, is more important for building fitness, thus the value of HIIT or running or swimming intervals, assuming high intensity is not done consecutive days.  But at upper athletic levels, they also do huge amount of lower intensity workouts, witness the incredible mileage put in by top runners and swimmers.

So I have no clear answer, but interesting question.

[JohnnyRow]

Thinking it over some more, I think at that level, you might have to start out by defining "fitness" for yourself.  For many people it might mean reducing risk of cardiovascular events to a reasonable level.  But to some it might just mean increasing your VO2 max as much as possible as a measure of cardio fitness, while this might mean ignoring any weight lifting or body-building, exemplified by world-class marathoners, perhaps the epitome of "fitness" but probably not the look most of us aspire to.  Or at one time many years ago, fitness to me just meant my time in recreational 5K or 10K races.  For people spending that much time exercising, perhaps it should broaden into looking at total life fitness to include all aspects of one's life.

[YachatsMike]

The Fitbit calorie counter counts Basal Metabolism Calories, too.  Those are the calories burned just to keep you heart beating, your body warm, your lungs pumping and your gut processing food.  My BMR is about 72 Calories / Hour.

[RodneyJ]

I've been testing all of this out since the year begin. It really has been a strange experiment. Burning 5,000+ calories per day resulted in very few Active Zone Minutes for me.......mostly because I was relying on walking(I was walking up to 3 hours per day, up to 49,000 steps per day). I had multiple days of 5,000+ calorie burn(I'm 212 pounds, resting heart rate is 52, and I'm 56 years old). However, I've had Active Zone Minutes of less than 10 on many of those same days(some days I had zero). On the flip side, on the one day per week I go for a 3 hour bike ride, my Active Zone Minutes are above 300.....but if I don't keep moving during the day, I won't hit 5,000 calories burned for the day. So when I'm done riding, I do all of our yard work right then.....to keep the calorie count up. I've had a really frustrating time with AZM too - not only does it NOT count most of my walking, it doesn't count most of my weight training either. And, even worse(for me), I get very few Active Zone Minutes when playing with my young daughter out in the yard....where we are constantly in motion, running, sprinting, playing, etc. My calorie count goes higher when we play(or when I lift or walk, etc.).....but I may not get a single AZM.

I started this discussion because I really wanted that "one" metric to pay attention to....instead of complicating it by looking at everything. But I'm finding drawbacks in both Calories Burned and Active Zone Minutes. For instance, concentrating on only Calories Burned......with my AZM being fairly low......my 5k times actually got slower. In addition, my energy levels playing outside with my daughter decreased. I felt like I had lost that explosiveness I once had just a few months prior - and I also noticed we weren't playing quite as hard or as much as we did. My weight training became almost non-existent because I had spent time concentrating only on AZM......and my weight training days hardly showed up in that metric. Even worse, my motivation to play with my daughter started to decrease.....because I started to wonder "Will I get any Active Zone Minutes if I play outside with her????" I mean....crazy.

To top it off, I do wonder about the AZM metric itself. I get one AZM if my heart rate is 131......but 2 if it goes up to 132? Uh...okay. I have adjusted my heart rate zones to reflect my resting heart rate and max heart rate.......but the Active Zone Minutes don't count all my activity, obviously. I feel like Calories Burned captures almost all of it(I double my heart rate while walking compared to sitting......but almost none of it is considered Active Zone Minutes). In an hour weight training session, I might get 5 AZM if I'm lucky. But my heart rate is elevated the whole time when compared to sitting. Playing outside with my daughter - my calorie burn can be quite high(over 1,000 on many play sessions), but my AZM might only be 5 or 10. In turn, concentrating on Calories Burned seemed to impact my overall fitness because I was relying so much on walking.

So....I'm at a loss. My Fitbit Versa 4 is starting to age. I'm due for an upgrade - or a replacement. But I'm not totally certain if I'll get another Fitbit or not. It's been "fun" in a way to look at these numbers - but I also wonder about what it's doing to my brain and my motivation. I'll say this - both of these metrics I concentrated on took its toll on my body. I mean, it's not easy trying to hit a certain number each day or each week. I did lose weight with the Calories Burned method - about 7-8 pounds in all. But I actually gained weight - about 10 pounds - when I concentrated only on AZM. Not sure if that's because of water retention or muscle(primarily legs).....or because I wasn't burning as many calories(my diet was primarily the same). So.......I'm at a loss.

[JohnnyRow]

You said your 5K times got slower.  If you are talking about running, or not, you should be doing some exercise intense enough to be getting AZM.  For pure fitness AZM are a better measure than calories burned.  And if you are walking 3 hours a day, then doing yard work plus lifting weights, of course you are going to be tired.  Spend less time exercising and take time to play with your daughter.  When you take your walks, vary your intensity, increase our speed for a few minutes to get your heart rate up into the appropriate zones, then slow down, until you get your breath back, then repeat, and you don't need to go for so long.

Don't let excessive exercise goals control your whole life.  And it's okay to take a day off.
You say you have adjusted your heart rate zones to reflect your resting heart rate and max heart rate.  Those should be set automatically with no need for adjustment, unless for exceptional cases.

You mention your Versa 4 starting to age and are wondering about an upgrade or replacement.  I suggest caution about that.  Unless you really are having problems that you don't think might just be in the settings, I've seen many that just had the itch to "upgrade", then found their newer model really wasn't better than what they had before.