Whenever I hear the second movement of the Moonlight Sonata, I get an image of Charlie Chaplin on one of those trolley things on the railway lines, trying to get away from the cops or Buster Keaton in the silent films!! I should think this would be a good one for the running machines!!
If you want big and bold, I'd go for the 1812, then to wind down in the jaccuzzi afterwards, I would have the Pastoral (Symphony No. 6).