Cardio Fitness Score

[speno1981]

Has anyone had any problems with their cardio fitness score decreasing?

I had a fitness score of approx. 46 ( v.good to excellent range ) then after doing a run ( 3 miles in 30 mins) it decreased saying that i had a poor fitness for my ages .. down to 24!

I currently train 2- times a day .. running for 30 minutes and 2 spinning classed for 120mins.. so surely this must be wrong?

Can it be reset?

[USAF-Larry · Accepted solution]

@speno1981, it is normal for your Cardio Fitness Score to change after a run of 10 minutes or more using Connected GPS. The app is designed to recalculate your fitness score based on the results of the run.  Prior to the run, it used an estimated fitness score based on your profile information.

[andrewilliamson]

Isn't the recalculation silly if the run isn't representative? For example, I use my Blaze most of the time. Yesterday my Blaze was drained, so I recorded a short, slow, recovery run on my Charge 2, and voila, the system has lowered my cardio score and notified me I'm in worse shape.

Seems silly, a mistake in methodology. There ought to be a setting that sets your cardio based on your faster/fastest runs over a given period, not based on any old run.

It's not like you lose fitness from one day to the next.

[KarinJW]

I'm having the same problem. My Cardio Fitness was in the Very Good range and almost in the Excellent Zone. I've been out on a lot of runs this week recording one of my fastest times a couple of days ago. However my score decreased by a couple of points during the week (before my fastest run).  After a more leisurely run tonight for 30 minutes I've dropped into the Good zone. This makes no sense to me at all. I mostly use GPS and go on runs for more than 10 minutes so by the answers given my score should be pretty accurate.  As I'm getting fitter and increasing my running, my Cardio Fitness Score is decreasing. Fitbit need to sort this and provide a fix. 

[Chewi789]

Can your cardio score be effected by using the cycle multisport selection while connected to GPS? If not why not? I'm useless at running but I cycle to work.

[Larissa121]

I am having a similar problem. My score was average, around 37. Then I went for a run with my husband. He is pretty out of shape and I wanted to stay with him to encourage him so I ran much slower than I normally would and when I was finished, my score had dropped to 30. Is there any way to exclude certain runs from the fitness score? 

[Chewi789]

Not sure but if you delete that run it won't count towards your score I guess. I just want cycling to count towards my score as I can't run

[milenita]

I have the same problem 

[Mshelby]

I understand that your score will change after a run.  However, it does not make sense that your score changes from excellent to poor after a 30 minute run.  Please explain how you can be less fit after running.

Thanks!

[Karencita]

This happens to me all the time! I jog with friends who go slower and, bam! My score immediately lowers. It is also possible to bump up the score by a quick 10 minute sprint. 

[Annehjy]

I have the same problem I have gone from 150 pounds to 140 pounds I've exercised every day and gone on 219 mile runs but my card it was dropped from 41 to 30

[Bray79]

Same here. I am to the point where I don't even look at it. It's so frustrating. I lift 2 days a week  and run three. My times are improving as is my heart rate but my fitness score keeps going down???? This makes no sense

[bbarrera]

Something is clearly wrong with Fitbit estimates, and they have some work to do.

I've wanted to try Fitbit VO2max estimation and compare to Garmin, however I don't run - I cycle 4-5 days a week for 6-10 hours. My Garmin bike computer uses a patented algorithm to determine VO2max. My score is stable, around 42 or 43, and not affected by easy rides. My fitness level (speed/power) has jumped 20% since January, but VO2max is only up 4% mostly from losing weight. That is normal and expected result based on sports science that has studied impact of training on VO2max. On the other hand, a beginner might see VO2max increase 10-20% after months of consistent training. Weight loss without muscle loss will also cause score to increase, as your aerobic capacity is normalized by weight to allow easy comparison of two athletes.

From sports science we know that for a well trained athlete, it is possible to temporarily raise VO2max thru very difficult interval training, but in general VO2max is more useful to show how you stack up against others. Therefore VO2max is a really good way for a coach to rank the potential of runners/cyclists/etc. It is not the best way to see increasing fitness levels for runners (5k/10k pace is a better metric) or cyclists (sustained power is a better metric).

I think "fitness score" is misleading, as it leads some to believe score will go up as you get faster. Instead it helps explain why a fellow runner/cyclist is faster or slower, because they were born with higher or lower aerobic capacity. Of course there are other factors, like running efficiency and lactate threshold. Both of those are more responsive to training than VO2max.

[roxy031]

I've concluded the cardio fitness score is a piece of crap and shouldn't even be taken into consideration. I'm giving up on trying to improve mine since there appears to be no correlation between the number and actual fitness. 

[bbarrera]

@roxy031 I agree, 'cardio fitness score' aka VO2max isn't of much practical use. From sports science the score is unlikely to change much, if at all, when you are already fit and in good aerobic shape. There are better practical measures of tracking improvements to running fitness, cycling fitness, etc. 

[Annehjy]

Thanks! I feel better now! I'm going to ignore it as well.

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Anne

[Karencita]

Pretty much: a score that can be manipulated so easily probably isn't worth a whole lot...  Still, maybe they will improve the algorithm. 🙂 

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@Karencita wrote:

This happens to me all the time! I jog with friends who go slower and, bam! My score immediately lowers. It is also possible to bump up the score by a quick 10 minute sprint. 

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[bbarrera]

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@Karencita wrote:

Pretty much: a score that can be manipulated so easily probably isn't worth a whole lot...  Still, maybe they will improve the algorithm. 🙂 

I hope so too, but after using Firstbeat VO2max estimation technology I think Fitbit would be better off licensing the proven technology rather than half-hearted attempts.

Regardless, I'd rather see Fitbit focus on metrics that are more reflective of changes in fitness for an event like my Wed night group rides. After a very strong May (2 centuries and double century), last month I took a break from training and riding. Yesterday my VO2max shows a drop of 4%, however my 1 hour power has dropped 22% and average speed dropped 15% (and not 22% because I can hide in the paceline and still go pretty fast).

[JohnnyRow]

As to the people seeing fitness score drop after easy run, I thought fitbit was supposed to be taking that into account by comparing heart rate to speed so even if you were going slower, it would see your heart rate was lower and know you were not working that hard. Apparently that is not working as intended.

I have a different issue with it. I have always had identical good to excellent score, presumable based on my low RHR, though I know I am not in that kind of shape.  In the past few weeks, in order to see how my score changed, I have for the first time gone on three one-hour GPS-connected runs, which are suppose to update fitness score, but my score has not budged one bit. Actually they were all 1-hour walks, not runs, but I told fitbit they were runs so they would be used for fitness scores.

[Goldblum57]

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@JohnnyRow wrote:

As to the people seeing fitness score drop after easy run, I thought fitbit was supposed to be taking that into account by comparing heart rate to speed so even if you were going slower, it would see your heart rate was lower and know you were not working that hard. Apparently that is not working as intended.

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Yes. It appears the only way to bring your Cardio Fitness Score up is to do a 10 minute sprint.  Any time more than that, you risk your score decreasing.  If I do a 5K race, in which I have only a slightly slower pace than the 10 minutes sprint, my score drops.  Fitbit doesn't appear to understand the interplay between pace and distance (putting heart rate aside for the moment).  It seems that, for runs longer than 10 minutes, Fitbit simply looks at the average pace for your overall run and applies in relation to the distance you ran in just the first 10 minutes.  If true, this of course is extremely inaccurate.

So, for the sake of argument, if you run 1.25 miles in 10 minutes (pace: 8:00) but later run a 5K with an average pace of 8:30, it seems your Cardio Fitness Score will actually go down after the 5K due to the slower pace, even though most would agree that maintaining an average pace of 8:30 for 3.1 miles (for a total time of about 26:20) is a stronger fitness showing than a pace of 8:00 for 1.25 miles (a total of 10 minutes).

I imagine for longer races, the drop is even more substantial.  And if you simply want to take an easy/recovery run, as some have mentioned, your score will become dismal.  The methodology Fitbit appears to use is flawed.  It should ignore easy runs and/or have a better interplay between pace, distance and heart rate in order to accurately calculate your Cardio Fitness Score.

(I could be entirely mistaken, but this has been what I have observed.)