When running, music seems to keep me energized. The playlist I have now starts at a fairly quick tempo and increases slightly toward the end. Since I tend to stay in rhythm with the music, I find myself running faster without realizing that I'm putting in extra effort.
This bit I think is particularly interesting:<p><i>But there are limits to the benefits of music, and they probably kick in just when you could use the help the most. Unfortunately, science suggests that music’s impacts decline dramatically when you exercise at an intense level. A much-cited 2004 study of runners found that during hard runs at about 90 percent of their maximal oxygen uptake, a punishing pace, music was of no benefit, physiologically</i><p>Listening to music can get me pumped up for lifting weights, but it's a distraction when I'm actually doing it.
Writing code to any fast-paced song (instrumentals only, though) tends to up my mental energy toward coding. Take away my chair and let iTunes pick the proper song and plenty of stuff gets written. It's a mood modulator for me, if anything and that helps with code.