Keep in mind that my requirements for exercise music are much narrower than my requirements for general listening music. In addition to the tempo requirements, it has to be a piece I know like the back of my hand because the more familiar I am with a piece, the better it creates time-slippage whereby the song exists both in eternity and in an instant. I use the "instant" function for exercising rather than the "eternity" function. So while I have a few performers in the exercise playlists that I've become relatively recent fans of (like Melissa Etheridge, the Dixie Chicks, et al.), the vast majority of songs that fit the criteria are going to be ones I've been listening to for a long time. Another reason I stick with very familiar music is the "no drastic tempo changes" aspect -- unless I know the song well, I don't know what the tempo profile is likely to be. There are a lot of songs even by 70s & 80s performers in my files where I'm uncertain of the tempo profile so I haven't put them in a set yet.