about 1 5 to about 5 minutes preferably about 3 minutes and a recovery section with a time period of about 3 to about 8 minutes preferably about 5 minutes in one embodiment the target heart rate reference intervals include the following intervals a target heart rate reference of about 70 of maximum heart rate for a time period of about 10 minutes a target heart rate reference of about 90 of maximum heart rate for a time period of about 4 minutes a target heart rate reference of about 70 of maximum heart rate for a time period of about 3 minutes a target heart rate reference of about 90 of maximum heart rate for a time period of about 4 minutes a target heart rate reference of about 70 of maximum heart rate for a time period of about 3 minutes a target heart rate reference of about 90 of maximum heart rate for a time period of about 4 minutes a target heart rate reference of about 70 of maximum heart rate for a time period of about 3 minutes a target heart rate reference of about 90 of maximum heart rate for a time period of about 7 minutes and a target heart rate reference of about 70 of maximum heart rate for a time period of about 5 minutes preferably the initiating.