Listening to an iPod while working out feels like second nature to many people, but University of Alberta researcher Bill Hodgetts says we need to consider the volume levels in our earphones while doing sports. His research has found that exercising in a gym often prompts people to turn up the volume to potentially unsafe levels for the ear, according to ScienceDaily. It isn't the listening level alone that's risky, it's how long a person listens at that level. What Hodgetts found is that almost half of his study participants listened for a length of time during exercise that put them at risk for hearing loss. The solution is simple, he says: get better earphones, those that "seal" the ear canal, acting as an earplug and thus reducing background noise.