Fitbit versa spinning calories accuracy/ margin for error

jmsspr93

Hi, recently got a versa and started exercising using the spinning mode. I set the goal to 200 kcal, when the calories were met on my watch, the bike said 110, compared to my Fitbits 200. My question is which is more accurate. My first guess is the Fitbit as it has my weight and height etc, but I assume it’s all based on my HR, so is the 200 burned on the Fitbit accounting for the 200 burned exercising or overall burnt at that time too? I don’t want to overestimate how many calories I’ve burnt, so is there a margin for error I should account for I.e 20% less or is the calories burnt on my Fitbit quite accurate, thanks again.

janejellyroll

Some people have found their Fitbits to be very accurate (I'm in this group), while others find they over- or under-estimate. Unfortunately, nobody can tell you what group you fit into. You pretty much have to figure it out through observing your own data and results.

If this is for the purposes of deciding how much to eat, many people begin by eating back just a portion of their exercise calories. If they find that isn't enough (which they'll observe over time because they're losing weight unexpectedly or losing faster than they expected), they then begin to eat the rest of them.

BrianSharpe

The problem with estimating calories based on a heart rate monitor of any any type is that there is not a linear correlation between heart rate and calories expended - all they measure is heart rate and time. Does the bike, by any chance, track your wattage? For cycling it's the only truly accurate way to determine energy expenditure. Based on watts my 45 min ride, averaging 31.1 km/h (approx 20mph) I burned about 340 cal.

Weight also has very little to do with cycling calories unless you're actually riding outside and climbing hills.

Without knowing how long your ride was and at what intensity it's impossible to determine which is more accurate (in which case I'd suggest going with the more conservative number).

cwolfman13

jmsspr93 wrote: »

Hi, recently got a versa and started exercising using the spinning mode. I set the goal to 200 kcal, when the calories were met on my watch, the bike said 110, compared to my Fitbits 200. My question is which is more accurate. My first guess is the Fitbit as it has my weight and height etc, but I assume it’s all based on my HR, so is the 200 burned on the Fitbit accounting for the 200 burned exercising or overall burnt at that time too? I don’t want to overestimate how many calories I’ve burnt, so is there a margin for error I should account for I.e 20% less or is the calories burnt on my Fitbit quite accurate, thanks again.

The spin bikes at my gym shows your wattage and uses that to determine calorie expenditure. For cycling, it is the most accurate way to determine energy expenditure. I can't speak to the versa, but people generally fit into one of two groups when it comes to fitness trackers...it's either fairly accurate, or not really.

HRMs use HR as a proxy for effort...the problem with this is that the algorithm also assumes a HR of a person of at least average fitness. Someone new to fitness and at a low fitness level will have a higher HR performing the same effort (or even less effort) on an exercise than someone who is more fit...this causes energy expenditure to be inflated. HR isn't directly correlated to energy expenditure.

I use a Garmin Instinct and I find it to be relatively accurate as compared to the calorie expenditure my spin bike shows me, but it's usually around 60-80 calories more than what my bike tells me...that actually jives pretty well with my watch giving me a gross burn rather than a net burn like the bike is giving me.