My husband has cycled on the wind trainer 4 days this week, equalled to 4 hours. He said his calories burnt were lower today than the previous day. So the fitter you get the lower your calorie burn.
Then you'd have to increase your time to get fitter to burn more calories. Ultimately to burn what you use to burn you have to double your work. Does not seem efficient to me. A bit like a tolerance has built.
If I burnt 370 cals on a bike in 45 mins, if I get extremely fit I would have a lower heart rate and probably only burn 200 cals for the same time. Seems unfair. I dont really want to have to spend my whole day exercising to burn cals I use to burn in half that time. Sorry I'm talking in circles. Hope you know my meaning and thankyou.