Music instrument = calories?

Feathil

I recorded my instrument practice for today in exercise but I think it's too much calories being given - it was about 150 calories for an hour of playing woodwind etc. I know that it's a lot of breathing work but I don't think it gets your heart pumping like even walking would.

Where did they get the estimations from do you think? I don't think I'm going to record it again because it's too generous, and I'd only be matching calories above the desired goal... God knows what wednesdays would be like as I have 45mins lesson, 2 hours big band with bari sax and 2 hours wind band with clarinet - I mean, it's all sitting down! Strange, isn't it?