Fitbit DJ Idea

I've been thinking about this idea for a while: I wear my Fitbit all the time when I'm awake, and I realized that the Fitbit app has been collecting all that data since I first bought it in July. I'm interested in studying the correlation between the physical parameters (heart rate, walking/running speed) and emotion (calm, excitement, etc.) If I can model somehow the relationship, I can develop a music recommendation system that will boost my workout more effectively by choosing the "right" song at the right moment. I should look into Fitbit's API..