Fitbit or treadmill more accurate?

[JJAnBan]

I just completed my W8, D3 run. I was using an 8 week program, so I did 30 minutes today. I suffered pretty horribly through my two 28 minute runs, so I took the advice here and slowed down just a bit. What a difference! No suffering at all! I’m really happy. I’m at not quite 2 1/4 miles on my Fitbit, but my treadmill puts me at about 2 miles, a pretty big difference. I always think my Fitbit shorts me steps and mileage on my walks, but I’m really not sure what to think. When I transition to outdoors, I can try runkeeper and see what that has to say.

In any case, the 5k I registered for is June 3rd, just 10 days before my one year anniversary of completing chemo (for the second time). My goal was to prove to myself I’m healthy enough to run 5k, and it’s looking promising!

Thanks for the support!

[John_W Graduate]

I suggest that the treadmill is much more accurate than your Fitbit. Fitbits tend to be made and marketed as lifestyle products rather than dedicated running devices - they don't have the best reputation when it comes to accuracy for running metrics.

Good luck for the 5k - what you've achieved having come through chemo twice is amazing.

[JJAnBan Graduate in reply to John_W]

Thanks, John. Makes sense. I’ll just keep going.

[CarverD]

Once you can get outside on a track or a measured distance you can get a better fix on how accurate your Fitbit is. I would agree with John that the Fitbit is most likely less accurate than the treadmill. On the other hand my Apple Watch has proven to be more accurate than the TM.

Congrats on your upcoming anniversary! Enjoy the 5K and remember that slow running is good running!

[JJAnBan Graduate]

Thanks, Carver! I’m hoping, of course, that I’m faster than my treadmill claims. I was never a very fast runner when I’ve tried this before, but nowhere near this slow. I’ve never used a treadmill until now, so I was hoping people were going to tell me they were wildly notorious for underestimating! Lol

[MissUnderstanding Administrator On a break Graduate]

My Fitbit is hit and miss depending on signal. On my parkrun, it’s spot on for 5k. The half marathon I ran was apparently a kilometre further than the course! Sometimes it definitely comes up shorter than the actual distance. When you do your actual 5k, you’ll have the adrenaline of the event to carry you through, even if you’ve trained over a slightly shorter distance. I wouldn’t have thought that the difference in distance will actually be an issue on the day.

Really good luck to you!

[JJAnBan Graduate]

Thanks very much! I did a little experiment this morning. I’m going to post about it soon.

[backintime Graduate]

My experience is that the treadmill may or may not be accurate but it is very consistent. When I wore a watch for a very brief period, or even runkeeper, it depends on how many points it finds to ping against. On one of my routes along by the river, there seems to be a "hole" where runkeeper shows me going about 800m extra, so obviously that mucks up distance and pace calculations. Two different phones with runkeeper have me varying slightly on the same route too.

[JJAnBan Graduate]

Thanks, Backintime. The consistency makes sense. I was hoping to know how far I still am from 5k. Today I did a 5k walk outside to compare Runkeeper to my Fitbit. When Runkeeper said I’d completed my 3.1 miles, the Fitbit was still .86 of a mile short!