These free streaming services will keep the tunes ( and the sweat ) flowing

Rdio ( rdio. com)

Thirty million songs and

countless mood-appropriate “stations,” like Cardio Workout and

Running Music—no FM or AM dial required.

Fit Radio ( fitradio.com)

The perfect marriage of art (DJ-curated playlists) and science (mixes that are designed to keep your bpm consistent throughout

your workout). n