It seems so obvious. “You want to listen to your music to pump you up, but in order to do that you’ve got to actually drown out the background noise,” says Dr. Hodgetts, a University of Alberta researcher who recently published a paper in the International Journal of Audiology titled, "What is the influence of background noise and exercise on the listening levels of iPod users?" He found, “You want to listen to your music to pump you up, but in order to do that you’ve got to actually drown out the background noise,” no surprise. [caption id="" align="alignleft" width="198" caption="The Etymotic hf5 seals deep and sounds terrific."][/caption] He observed stock iPod ear buds “allow too much background noise in. And so, if you get a set of headphones ... that just seal the ear canal, then you immediately cut out the background noise and you allow the vast majority of listeners to listen at a much safer level.” Seems obvious. What's not so obvious is that there are basically two different types of in-ear headphones: those that seal deep and those that seal shallow. The shallow seating kind split the difference between isolation and remaining aware of your surroundings and are good for outdoor exercise where it's good to retain a little more situational awareness. But for indoor time at the gym (also air and train travel), where you really want to shut out outside noise, the deep seating style is preferable. [caption id="" align="alignright" width="198" caption="Shure in-ear cans seal deep and have many tips to choose from."][/caption] I suggest the Lines of products from Shure and Etymotic, which all seal more deeply in the ear. Both brands have a variety of ear tip styles; you may have to experiment some to find a perfect match for your ear. When you do, both the isolation and the sound will be much better, and you'll be able to enjoyably listen without turning your music up to unsafe levels. Dr. Hodgets paper may be purchased here; news on this topic may be found here, here, and here.