[Additional info added 3/13/13, after writing the review. The following sidebar info (by Meaghen Brown) was published in the April 2013 issue of Outside magazine, page 76 in an article by Brent Rose entitled Play It By Ear. It’s noted on their current magazine web page, but with no hotlink ( you gotta buy the mag):
Fatigue– music reduces perception of fatigue by 8%.
Time Flies– perception of time speeds up to 12%.
Get the Rhythm– as a beat generator, tempos of 120 to 140 offer the greatest benefit.]
My rating: 3 of 5 stars
Quite useful, but repetitive, yet already dated (2012). Two medical doctors ( and a MBA) cite neuroscience backing up the practice of listening to music in order to moderate consciousness. The practice of ramping up and damping down via acoustic input has been a part of human existence for many thousands of years. Vibratory effects of sound have been well known, primarily in religious contexts. For example, Vedic tradition of mantra use for specific physiological effects.
Listening to my iPod while backpacking, bicycling, and walking has clearly resulted in elevated energy, increased happiness, surprising releases of emotion ( like crying), and help from boredom.
On my 2,700 mile Pacific Crest Trail, I used my iPod sparingly, due to battery life. It was engaged in late afternoons, when I was fatigued after 20+ miles, and had the effect of increasing my flagging pace. It is also effective on uphill climbs. In some instances the perceived effect was equivalent to the energy increase from eating a 200 calorie energy or candy bar.