Exercise Bike/Calories Burned

[RightsaidMum]

Hi all.

So I've recently got a recumbent exercise bike. It's a Nordictrack.

The bike tells me how many cals I burn each session.

It is wildly lower than what my fitness app tells me I burn in the duration I input. For example:

Today I used it for 30 mins. Varied resistance levels. Speed average 12.5. 7 miles. It told me I burned 162 cals.
I then logged it into Samsung Health as "exercise bike"- which only gives an option to enter the duration of the exercise - so 30 mins - and it said I burned 368 cals.
I then tried out entering it as "cycling" rather than "exercise bike" - which allowed me to enter my mileage PLUS duration - and it gave me 247 cals burned.

My fitness app is linked to my weight loss logger, and it's important to me to see how long I'm active for over the course of the day and to see the deficit I'm earning myself for weight loss.

Are exercise bikes generally the more accurate in telling cals burned? I tried the maths way with finding my BMR etc to calculate how many cals I would burn during exercise but it's HARD to figure out.

Problem is intensity varies, so the duration-only one isn't good enough.

There is a formula to figure out how many calories you burnt, depends on your
sex
mass
heart rate
vo2max

1st var doesn't change, 2nd var changes slowly, last var can be assumed (charted average for your age+sex), and HR can be measured directly during the activity, for intensity of effort. Just saying distance isn't useful to indicate effort because 12 miles all uphill would obviously be different from 12 miles on the flat.

I dunno about exercise bike method, does the exercise bike know your sex + mass + heart rate? Does the app know your mass today? On top of that, some of the methods only calculate the calories that are excess to you staying alive -- they deduct the BMR for that time, I suppose.

My guess (comparing to my Fitbit estimates* when I cycle for ~30 minutes) is 162 kcal is your best estimate as an indicator of the extra calories caused by the exercise over BMR.

*Fitbit knows my heart-rate, sex, mass