In general, a computing device disposed in a cardio exercise machine receives data related to a fitness level of a user. The computing device selects a workout program based at least in part on the data. The operations of the cardio exercise machine are controlled based at least in part on the workout program. The computing device generates audio feedback based on at least one of the user's operation of the cardio exercise machine and the selected workout program. The processed data is stored on a removable computer storage medium that is insertable into a port of the cardio exercise machine.