Most of us decide intuitively that music reduces the pain of a workout, and it turns out there are some research findings to support this hypothesis as well. Many people are aware they can change their mood with music, naturally a good mood elevation during a stressful workout is often just what the doctor ordered.
Music keeps us going harder for longer, it naturally increases the effort level of the workout. It not only distracts you from the pain, but stimulates your brain in the right places. However, if the BPM is too high (above 140bpm) the effect appears to be diminished, information overload.
As you grind on, the infectious rhythm of a good song will entrance you, trending your motions toward even time. Music is shown to engage the motor areas of your brain, that is to say, it keeps the pace. All those times you found yourself dancing before you noticed? It wasn't just your imagination, groovy music will really groove you!