[Shizdan]

I have been using my Senn IE7 IEMs while I run 3 miles every other day for the last week. They dont fall out and I love the sound. But is it safe to wear them? I dont wanna break them....

 

[Rip N' Burn]

They don't isolate too well so you should be more aware of your environment while running which is a good thing. The only thing that I would worry about is any debris or sweat getting into the vents which can damage the driver. Covering them up with some tape should help.