Count the beats per minute in your exercise music. Listen to the solid downbeat followed by a slightly less intense upbeat. Count the number of downbeats during one minute of steadily paced music to determine the bpm. Or, look at the bpm listed on the music title if you are using an exercise-specific song. Match each step when walking or running to the music's downbeats so that you maintain a constant speed.
Determine your stride length so that you can calculate your mph. Stand outside or in a long hallway with your feet together. Place a pen in front of your toes. Walk or run, depending on which stride length you're calculating, for 10 steps. Count each foot strike as one step. Place the other pen in front of your toes of the foot that took the last step.
Use the tape measure to calculate the distance between the two pens. For example, it may be 320 inches. Divide the distance by 10 to determine your step length. For example, 320 divided by 10 equals a step length of 32 inches, or 2 feet 8 inches.
Use this formula to determine your mph: bpm times stride length -- in feet -- times 60 divided by 5,280. Multiply the bpm by your stride length. For example, 150 bpm times 2.5 equals 375. Multiply the result by 60, since there are 60 minutes in an hour, and if you maintain a constant pace, you will remain at the same bpm for an hour; 375 times 60 equals 22,500. Divide the result by 5,280, since there are 5,280 feet in 1 mile, to convert to mph. Thus, 22,500 divided by 5,280 equals 4.26 mph.
Use the following, for an approximate mph conversion, calculated by the Medical and Sports Music Institute of America, to change bpm into mph and monitor your walking workout sessions: 120 bpm equals 3 mph, 130 bpm equals 3.5 mph, 140 bpm equals 4 mph, 150 bpm equals 4.3 mph, 160 bpm is 4.6 mph, 170 bpm is 5 mph, 180 bpm is 5.5 mph and 190 bpm equals 6 mph.
Use the predetermined paces from the Medical and Sports Institute of America to calculate your approximate running speeds: 150 bpm equals 6 mph, 160 bpm equals 6.7 mph, 170 bpm is 7.5 mph and 180 bpm is 8.8 mph.
Select slower-paced music for walking and faster-paced music for running. For example, listen to music that is 120 bpm for a 3-mph pace, or music that is 190 bpm for a 10- to 12-mph pace.