Originally Posted by
guachi
This is exactly what I do. My HRM vastly overestimates my calorie usage by 30-50%.
On the other hand, the HRM is great at measuring how hard my rides feel. The other major benefit is my max heart rate doesn't change as much as my FTP does.
Combining a PM and HRM has shown me that I can put out far more power inside on a trainer than I can outside for a given heart rate
I don't bother with calories for anything. I just weigh myself. Enough navel gazing time for me. I find your last assertion to be true for me. The word is "arousal." That's what you have on the road which gets your HR up and what you don't have indoors. My HR always sucks indoors, which makes the workouts harder, HR being hormone driven. Sometimes I'll yell at myself, make weird aggressive noises, That helps maybe 2 beats worth. I ride indoors in a cool room with a big fan, no shirt. Cooling is fine. A lot of the time I get the perfect temperature indoors: 55°.
Since my HR is higher outdoors, it's easier to put out more power, period. I can do stuff outdoors I just can't do indoors, too much pain. Blood flow = oxygen = aerobic power and lactate removal (or whatever).
I agree about the calorie counting. Kinda doesn't matter how accurate the count is as long as it's consistent. You get a number and respond by budgeting calories in response to that number.