Cardio Fitness Score accurate?

[emmasawr]

Hi there! I've had the Charge 2 for a few months now (got it back in December) and I've been wondering how accurate the Cardio Fitness score is, and how exactly it is calculated. I currently have a 33 (which is poor for my age) but I don't think I have poor fitness. I'm 19 y/o female and I exercise regularly, as I'm a pretty avid runner. I'm also currently in college living on a big campus, so on a regular day I take at least 10K steps without exercise, and up to 30k with exercise. I run 4-5 times a week, running 3-10 miles per day depending on my training schedule, usually averaging out to 20-35 miles per week. I know the score is based on VO2 max, however, and I do have exercise-induced asthma. My HR to get pretty high during exercise, especially when running up hills (I take a couple of puffs of my inhaler before I go out for runs). Thanks for any insight! 🙂

[dhirenpsingh]

Agree with that. when i was barely able to run 5K, I was at 51. Now I am able to run a Half Marathon and stuck around 46.

[AdrienneMarie36]

I am on the same page as well. I teach Jazzercise 3 days a week, do cardio kickboxing once a week, heavy weight training once a week, and fill any extras spaces with running and yoga. Usually working out 7 days a week. Mine is only in the "good" area and I know I'm a cardio queen! 🤣 Come on Fitbit. Lol.

[Paddymaree]

Yeah it's not accurate at all. I'm a 3:40 marathoner and it had me as just below average. I finally switched to Garmin and it has me in the top 5 percent of women my age which sounds a lot more accurate as that's where I usually place in races.

[JoeC657]

I basically can’t run any substantial distance and limited to about 5-6 mph. My cardio fitness level is 53-57 according to Fitbit. I have a very low resting heart rate (probably inherited) but my red blood cells are significantly smaller than normal or average (probably inherited also), therefore limiting my exertion level. Another strange physical is that I am minimally affected by elevation. I see no difference in performance at 10,000 feet.
As Stated before, Fitbit is useless in comparing your performance to others because of various personal physical differences. It’s to be used as a gauge for improvement of your own physical performance over time. If you are already at the top of your game, you have nowhere to go for improvement and will see little if any change in your Fitbit numbers. If you stay in great cardio shape as you age, your Fitbit fitness level should rise as age is one of the factors.

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[AdrienneMarie36]

I'm probably switching soon.

[sjmitch]

Hi JoeC657. The problem I have with Fitbit is that I had made positive changes to my health and I can see the differences (physique/improved times) but as far as fitbit is concerned an increase in muscle mass increases my BMI and thus reduces my cardio fitness score.

[RenoRichard]

When you are entering your weight, there is a place underneath to enter your % of body fat. If your % of body fat has gone down from muscle building, this may offset some of the effect.This allows some flexibility. If you are also entering your % of body fat as well, then you are correct. 

[Sienna-Rose]

Precisely why BMI is a useless indicator of health on its own.

[EmmaLewis55]

I run 6 or 7k in 30 minutes daily, get 15000+ steps every day, have a resting heart rate of 54 and my cardio fitness score is 32, which seems really low with my lifestyle. I don’t think it’s accurate

[Ajgreez]

Yes, this exactly!!

[MTglass]

I agree I think a lot of lot depends on heart rate.

I have a high max for may age (54 years) of 190 and low resting of 56.

My score is 54 I am fit and train 4 times a week but I still think the heart rate difference is key and a lot of that is hereditary, I have always had it even when I was less fit.

Interestingly an online V02 calculator which asks a lot more questions gave me exactly the same score.

If there is any benefit I think its whether your own score is improving or not.

[JoeC657]

Exactly! This is YOUR personal training assistant, not a universal comparator.

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[PeteG-1]

@MTglass 

Yep, I'm in the same category, I've been racing of some sort (running, XC skiing, DH skiing, road-bike, and more) since my early teens, and I too have a pretty high score, one that "ages out", in terms of my couple of "real VO2 max tests", back in the 90's (yeah, on a machine, with the breathing box, sensors, and stationary bike, when I was pretty heaving road-racing), most progressions put me in the 53-57 range, and that's often where all of my sensors estimate me (now a Garmin and Suunto), across a LOT of rides and other activities.

But, like you say, I could mostly care less what my cycling group (a mix if people actively racing, masters, CatX, MTB, Tri, Randonneuring, etc). friends numbers' are stacking up to, numbers-wise.  I care more about being able to ride safely/steadily, in the group, and maybe occasionally winning a "sprint section", or "taking a climb", that's way more fulfilling, than "comparing numbers" ;-]

My max-HR is still quite high, too, around 184-185, for my age, and my PCP could care less about it, he's fine with whatever; I think he figures I'll "black out", before I "blow a gasket" statistically.   
Since he started road-racing (later in life than me) though, he does have a "new perspective" on my riding, but he still never challenges my maxHR values, or even high-threshold rides...

[FBMum]

I am a Charge 2 wearer.  I have gone from just a couple of martial arts workouts twice a week to trying to train for a 5Km fun-run - I've been at it about 3 weeks.  Interestingly my Cardiac score has improved - 33.6 - 33.9 today 34 (which it finally says is Excellent for someone of my age) after last night's run.   My resting heartrate at best is mostly high 50's and I've done an online VO2 quizz and got very similar values.  I tend to think that the Fitbit must be making some sense of things and at the moment I feel encouraged by the increasing value.  So I'm not going to knock what seems to be a good thing as I find every increase an encouragement to something that I am not finding easy.  Therefore in that respect I think it has to be a good thing! 

[JoeC657]

You are using and thinking about the Fitbit correctly. It is for your own personal measurement only. How it relates to others, including the fitness rating, is not really relevant and only rated in general terms. Look for improvement in your own scores and lowering resting heart rate, which is key. Stress can also affect your numbers. Good mental health goes hand-in-hand with overall wellbeing. And yes, its main purpose is a motivator. Best wishes.

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[JCall]

Despite losing a fair bit of weight in the last few months, generally feeling fitter and being able to run for longer distances, and also my resting heart rate improving as a result (from 62bpm down to 47bpm) - my cardio score has decreased from 48 (which was in the GOOD) bracket, down to 43 (which is at the top end of AVERAGE)

When I first started running, my heart rate would remain high for a long time afterwards, but as I've improved, it returns to normal a bit more naturally, and I can run longer distances with an improved mile-time. Based on all that, I'd expect it to have increased rather than decreased in that time.

[JoeC657]

Did you reenter your new weight into your personal profile? Something else changed in your stats from when you first started with the Fitbit. Are you getting the resting heart rate number from your sleep profile, which is the most accurate, and official, method the Fitbit uses to determine your resting heart rate. If you are only looking at the lowest heart rate on the face of the device, that is not what the device uses to determine resting heart rate.

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[JCall]

Yes, new weight entered after each loss recorded (usually once weekly)

And yes, I'm getting the resting heart rate from the sleep profile, rather than my lowest heart rate (as quite occasionally, usually in the mornings, my idle heart rate is lower than what is recorded as resting).

[JoeC657]

Seems like you are doing everything correctly. If it were me, I would recheck all of my personal data entries to see if any of them changed, for whatever reason. If everything checks out, then there may be a glitch in one of Fitbit’s software revisions. So, check in with support to see if they can figure out what is happening with the numbers. Good luck and keep on truckin’.

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[Skinnytostrong]

Interesting... Mine has just dropped to 34 from 36. Not ideal. I exercise 1-2 hours most days but was wondering if it was because of my asthma... I get into the peak zone frequently and do HIIT, cardio and weights... (and hit the 10k steps no problem) But it’s getting quite frustrating! Maybe Fitbit can have something that considers asthma and adjusts accordingly? Be interested to know if there’s a medical link (oxygen in / out etc)...