The song goes at almost 100 beats per minute, which is the same rate that the American Heart Association recommends for chest compressions for CPR. The medical school at the University of Illinois studied the effects of having this song playing while doing CPR and they noted that practitioners were able to hum along the music and keep an appropriate rhythm.
100 beats per minute is perfect for CPR because it generates enough blood flow while letting the heart fill with blood properly between each compressions. People who even hum along to the song are better able to keep the beat steady. If you're a little more morbid, another classic song can also be used for this: Queen's Another One Bites the Dust.