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! 🙂

[JoeC657]

Just because you run it doesn't mean that you are physically fit. I've seen some pretty fat "marathon runners". Your fitness level calculation is based on height, weight, resting heart rate and age. This is not an absolute measurement of fitness but a fairly good estimate. My fitness score is 52-56 and I'm 69 years old, but I can't run for more than a few hundred yards due to a physical limitation which is offset by an inherited low resting heart rate. The fitness score calculator has no input on these conditions. However, for average people with no physical limitations, it's a pretty good measure of relative fitness. You want to be able to lower your weight, if overweight, and lower your resting heart rate, through exercise, to improve your score, since changing your height or age are not going to happen. This is where the Fitbit can help you. Wear the Fitbit to bed to get a more accurate estimate of your resting heart rate. Eat more vegetables, less meat and especially less starch (carbohydrates).

How did your resting heart rate change over this time period? If you lost weight and lowered your resting heart rate, your fitness calculation would have improved. If you don't wear the Fitbit while sleeping, it may not be getting a good estimate of your resting heart rate.

Moderator edit: merged reply

[Paddymaree]

I know im pretty fit. Im not fat my body fat has been properly tested and it's at 23% which is in bottom 20 percent for my age. I also do weightlifting and I'm usually in the top 5 percent of women in my running races. I train 6 times a week and I currently can run a half in 1:46 which is a well above average time. Since I got the Ionic it puts me at average for my age. I'm certain it's not accurate at least for me. It may be because I have quite a high muscle percentage which Fitbit can't tell. I'm not sure, but it annoys me that it says to do more GPS runs for a more accurate result and my result doesn't change despite the fact I run pretty fast. The Ionic also puts me in peak heart rate when I'm running slow and not even tired at all so maybe that has something to do with it.

[JoeC657]

Do you know your actual resting heart rate? What does the Fitbit say is your resting heart rate? Do you wear the Fitbit when you sleep? Wearing the Fitbit while sleeping will yield a more accurate resting heart rate. You may also have a high resting heart rate due to hereditary reasons. This will definitely put you lower on the fitness scale. As was also noted in another reply, the device is not accurate enough to gauge your fitness against others. You can only use it to show personal improvements. If you are already at the top of your fitness, there is little room for improvement.

I also found that the pace calculation while using GPS and iPhone on level ground (Florida) was not accurate enough for me use for interval (walk/run) training. The pace at times would get better while walking and worse or not change while running. This is because GPS is not accurate enough over relatively small distances so calculations can vary significantly as the unit updates during the workout. It was extremely difficult to maintain a selected average pace over my 3 mile route. I'd rather see my heart rate, not pace, displayed on the iPhone screen. I discovered that the unit would lose heart rate during exercise and cause my average heart rate stat to become falsely low. Even fast walking the entire route on back-to-back days showed radically different statistics. I wrote to Fitbit, including screen captures, and Customer Service tried to put the blame on me or excuse the problem away. In my humble opinion, Fitbit is not really ready for "prime time".

[Paddymaree]

I wear it to bed and my resting heart rate is about 60, which is relatively low and matches my fitness level. If it's only measuring my improvement that could make sense, when I got the Fitbit I was already very Fit and so my improvements have been small in terms of heart rate.

[PeteG-1]

I'm somewhat similar, I'm relatively fit, for someone my age (I just kept road-riding and skiing, fast, and have tried to ignore the age thing ;-]).

I find that my estimates (53-55 w/o GPS, 55-59 with), seem reasonable, for my level.  I'm 51, and range from about 8-9% in the summer to about 11-12 in the winter (skiing and just cycling part-time isn't quite as good, and the food is "heavier" overall, my excuse anyway ;-]).

I'm a "big muscle/medium-frame/low-ish fat guy, but by BMI standards I'm overweight, and in the winter I start to approach obese, hmm...

I can usually drop a fast 40-50mi ride in the winter without feeling too bad, ski 15-20 solid runs, and the the summer I'm more overall fit, most of my rides are in the 40-120 range (and "quick", by most peoples' standards), sometimes a double-century, maybe, it's been awhile now.

Anyway, I guess my point is, I'm not so sure I put all that much stock in the "fitness score", either way.

I've done a couple of VO2-max tests, in my 20's, when I was road-racing (bikes, again), and I'm pretty sure that my Fitbit doesn't even come close to what those machines are capable of, in terms of estimtes.

Sure, it could be "close", but it also might be pretty far off one way or another, too.  GPS helps, to at least "normalize" the numbers, but I still don't think it's a great estimate for a "real test", it's just a good way to approximate.

[JoeC657]

The Fitbit only tries to measure resting heart rate as you wear it, during sleep is best. You entered the other fitness factors (height, weight and age) when you set up the account and hopefully update the weight as it changes. So, the only wild card here is resting heart rate, which can change day-to-day mostly depending on stress levels but over time you can get an average and see the resting heart rate is going up or down, down is good.

My resting heart rate went up 4-5 points over 3 days as I was getting ready for a trip to Florida to visit my brother. It remained high for a few days in Florida until I settled into a routine. Taking it easy and exercising (daily 3 mile fast walks) got my resting heart rate to it's lowest level since December, when I got the Fitbit. Since December, my resting heart rate has dropped 10 points, probably because I exercise regularly now and did not before Fitbit. My resting heart rate went back up a few points again as I got ready to come back home and settled back down as I settled in again.

Meditation can help relieve stress and should be practiced daily, even several times daily. When I am totally relaxed, my heart rate will drop to 44 (lowest so far) but the calculated resting heart rate hovers around 51. Rated excellent for a 69 year old, but I feel age should not make any difference if you live a healthy life. On average, older people have higher heart rates. But again, are they taking care of themselves? I found through hereditary testing that I am "blessed" with a rare blood type and lower than average resting heart rate, but I can't run for any distance and VO2 max tests put me as physically unfit. Another curious thing, elevation, up to 12,500 feet, has little affect on my breathing while active. Climbing stairs on the top of Rocky Mountain National Park is no different than at home in Massachusetts.

We are all different and have unique physical properties which can not be accurately measured by $100 devices, or any device for that matter. Use the Fitbit to measure personal progress and nothing else. Keep exercising properly, update your weight as it changes, meditate often to relieve stress, and you should be fine. If you resting heart rate does not drop, you are probably as fit as you can be.

If you have an above average muscle mass, through strength training or heredity, whatever, the BMI height/weight scale will be off on the high side as it uses "typical" bodies for calculations. A chart can not tell fat from lean muscle mass and is useless for evaluating many people. As for me, I'm relatively short and skinny compared to most men but I was considered borderline obese in the charts. Trouble is, I sink in fresh water and can't swim for any length of time, therefore I dive. My body density is way higher than most people. The charts don't know this. While getting scuba certified, there was a tall skinny woman in the class who needed 20 lb. of lead, just wearing a bathing suit, to be able to stay on the bottom of the pool with the rest of us who needed maybe 6-8 lb. Go figure. The scuba instructor and I were the only ones who sank to the bottom of the pool with a normal lung full of air. Fully inflated, I barely float with just a small spot on the top of my head above water.

There are relatively accurate methods to measure body fat percentage which entail multiple measurements or water emersion and even electric current, but this is crazy. Be honest with yourself. Do you have excess fat or not? A chart certainly can't tell you and a little fat isn't the end of the world. Eat healthy (mostly vegetables (green), much less lean meat than you think is needed, occasional low sugar fruit, and stay away from starch and sugar) your weight will "magically" settle in where it is healthy for YOU. Best wishes.

Moderator edit: merged reply

[Castlenut]

Try tightening up you ionic one notch 10-15 minutes before exercise. I had same problem with heart rate jumping higher and this fixed it. Also, if you run hills the Fitbit won’t track that in your score. Resting heart rate does have big impact so make sure you wear tracker to bed and “wake up “ slowly. 

[JoeC657]

Thanks for the help. Sometimes the Fitbit gets too tight during exercise when I start a heavy sweat. The skin seems to swell a bit. The heartrate measurement, as shown in the exercise graph, is very inconsistent and I know it loses heart rate while I'm doing my fast walk or walk/run intervals. This throws off the average heart rate. No way will my heart rate go down to 70 in the middle of my exercise. The heart rate graph looks like a saw blade sometimes and other times (rarely) looks okay. Same me, same route, same exercise, same Fitbit strap setting and location. Plus GPS is not accurate enough to do relatively short interval calculations for the pace calculator. It's accurate to only +- 50 feet or so which throws off the average pace calculation as it updates. I'd much rather see my heart rate on the iPhone than the average pace.

[Castlenut]

Interesting about the GPS and Sprints. All my runs are 5-26 miles, so I am guessing it averages out my pace better. The instructions say go for at least 10 min run, so maybe that’s why. As for the resting heart rate, I think my Fitbit fails here. If I take it manually it’s 48-53 bpm. The Fitbit says 54-58 bpm. Long runs don’t impact my score much, as it’s all I usually do. I started at a 59 after training for marathon for 6 months and have eked up to 61. At 53 yo male, it’s a good number,so I like to pretend it’s accurate 😜

[JoeC657]

Seems like you have similar issues with resting heart rate. Because mine is a bit higher than actual, the Fitbit thinks I'm sleeping while watching TV, reading on the computer and doing relaxation exercises. This is a bit frustrating.

Try watching your phone app's average pace as you start your run, especially if you run at the same speed during this time. You will likely see the pace change up and down by several seconds and will average out and change less as you add up the miles. For me, this is very annoying as I am trying to keep an average pace over a shorter distance and the unit is lying to me, causing me to think that I'm ahead of pace then find myself behind and can't catch up. Crazy.

[jodes13]

I'm pretty late to this party considering the original question was posted over a year ago haha. This thread popped up for me, though, as my fitbit says I'm in the "Poor" category in my cardio score for my age (30 year old female). I'm a firefighter, go for runs 3-4 days a week, weight lift 4-5 days a week, go for 20+km bike rides on the weekends when it's nice, and am generally quite an active person. It was bugging me so much seeing that score; "What the hell, fitbit, you track my exercises. You know my fitness level. Why are you lying to me?!" I'm glad I'm not the only one who's been experiencing this. It's too bad there isn't a way to sort of re-calibrate it.

[JoeC657]

Don't get discouraged. The Fitbit is only a tool that primarily uses your resting heart rate to determine your fitness level. Trouble is, many people have naturally low resting heart rates due to genetics and others don't have this trait and may even have normally high heart rates. Generally speaking, the lower the resting heart rate the more fit the cardio-vascular system. Not strength, or stamina, or whatever, just cardio health as an average of the general populous. Use the fitness number when you started with Fitbit and properly train to improve your heart's performance. It is possible to go backwards through improper diet and training. Plus, any form of stress can and will raise your resting heart rate. Yoga and relaxation exercises can help a lot to relieve stress and lower heart rate. I've seen my rate go up 6-7 bpm when I had a respiratory infection and again 4-5 points getting ready for a trip to Florida. Once I was settled in, the resting heart rate came back down. I've seen my heart rate as low as 41, but the lowest number the Fitbit has assigned me is 49, based on my sleep patterns and heart rate while sleeping. If I have a restless night with little or no REM and deep sleep, my resting heart rate will likely bump up a few bpm. My problem with Fitbit is that it thinks I'm sleeping when I'm watching TV or sometimes doing research work (reading) on the computer. This is when I'm totally relaxed and the heart rate lowers.

In short, use the tool for a personal reference point and forget about how you compare to the rest of the world as this is the least reliable aspect of the device.

[Master668]

My current Fitbit cardio fitness score is 52, which is more than "excellent for your age", at 61. I've a pretty good resting heart rate (high 50's to low 60's) and BMI sits around 28 (overweight, but slowly trending better). I do regular (6-7 days a week) walk/jogs on the local hills and beach with the dog, and generally hit 10,000+ steps a day. That said, I'm no super athlete, so would regard the score as perhaps a tad optimistic for where I personally see myself, fitness wise. I'm certainly a heck of a lot fitter than I was a year ago, but there's no way I'm about to start running marathons!

[andrius.k]

That device is a joke, its totally inaccurate. Steps counting - its a bout accurate when you have started walking and finished walking. The rest of the day! I was able to do up to 9K of steps just sitting in the office. While driving , again it counts steps. Distance! 😄 ok when i do my 10km walking sometimes it will show the same number of steps but distance may be different form 6km to 10km even if i know i did 10km. Next heart rate my device was showing accurate heart rate only while resting , all the time i was training it was showing incorrect values, tested with heart and blood pressure monitoring device. While training it was constantly stopping heart monitoring at all or being stuck at the same value for the time when  stopping monitoring and recalculating again. So basically whatever i tried to get my max heart rate it  wasn't showing. I was advised to get some spirits and clean sweated wrist and device , can you imagine yourself while running you are cleaning your device with spirits??? Even if you take your device away from wrist it will keep monitoring your heart rate from the distance 😄 for about 30min until it will decide " im not on the wrist anymore" 😄 and values are changing.

So sorry for my grammar, but my opinion is : charge 2 is not accurate at all.

Got my one back to the shop took money back.

[JoeC657]

You are right. The Fitbit has a lot of issues and doesn’t work well during workouts and is easily fooled by waiving your arm around. It works okay (marginal) for walking or running while using your phone and GPS tracking. However, the pace calculation during the walk or run is off for short intervals because of GPS minor inaccuracies which average out over longer distances, so your overall average pace, when finished, is fairly close.

Steps are meaningless, period. Are steps taken on a level surface at 1 mph the same effort as taken at 4 mph or on a 25 degree incline (hill) or stairs? I think not. It is not a tool for serious athletes, just average people trying to measure something that shows movement vs non-movement.

Sent from Mail for Windows 10

[andrius.k]

it should cost 50€ max not 150€. I got samsung gear s3 classic as B-day present. Already did some tests and its way more accurate device regarding the technologies it has installed. The main thing i like that it shows heart rate all the time during workout no matter how wrist got wet. If you have it on autoactivity sense while you drive sometimes it is counter as activity but you can delete it with one click. At some points health app is much more easier to use and looks better. 
all i have loved in charge 2 was sleep monitoring that was great if i can believe it. Gear S3 has something similar but not that detailed as charge 2.
I found Samsung gear S3 is way more decent device even S4 is on the way, rumors say it would be able to test blood pressure. Of course charge 2 is only 150€ what is too much, samsung gear s3 goes near 400€ 

[Sienna-Rose]

I have a similar problem. Honestly, it seems bias to me. It assumed that because your weight is high you MUST be unhealthy, even if you are fit and healthy and have a low resting heart rate. 

[JoeC657]

Fitbit fitness score is based primarily on resting heart rate. Since a healthy resting heart rate is different for different individuals you can not accurately compare yourself with others. As for me I have a relatively low resting heart rate (genetically blessed) but is offset by a rare blood condition of abnormally small red blood cells, also inherited.

I have dropped my resting heart rate by 4-6 bpm on average since owning the Fitbit and raised my fitness score by 6 points (54-58) which is pretty good for a 70 year old. But I can’t run very fast for very long and have a very unfit VO2 max because of my small red blood cells. According to that measurement, I’m barely surviving.

In summary, use your Fitbit as a gauge to measure your own personal improvements and forget about absolutes and comparing yourself to others. Eat well, exercise and teach yourself to relax through mind control and breathing exercises. If you think you are eating healthy, read The Plant Paradox by Dr. Steven Gundry, it’s a real
Eye opener, and backed by 15 years research experience, published and peer reviewed.

Best wishes.
Sent from Mail for Windows 10

[Joejones90210]

It is very dependent on resting heart rate.

Also I run up hills a lot in summer and flat in winter (florida) the hill 

Running lowers my score by 3 points. 

Its neat but not accurate. 

Another thing I noticed is my heart rate at higher speeds of intense cardio is actually 155-160

The fit bit never records it at over 140.

So it's just a nice toy.

Ps

Always leave bluetooth GPS on your phone and take it with you during runs.

Pss

Make sure when on treadmill you use the treadmill setting and not running setting.

[Dani98]

I believe that as well i habe lost 35 pounds and 5 and a half inches and it hasnt changed and i dont get as winded anymore walking up to my third floor apartment i can run down the stairs now. Hasnt improved on here a bit.