Earbuds make jump rope noise matching w/ heartbeat?

I have a pair of apple earbuds that came with my iPhone 5 and whenever I lay down and my ear is on a surface a jump rope cutting through air noise comes through the earbud. I also took my pulse through my wrist and noticed that the noise matches with my pulse. Has this happened to anyone else?

Yeah, it's just sort of echoing the pulse in your ears like a seashell would, happens to me all the time. I got a pair of skullcandy earphones (the one with the gummy bits) and it doesn't happen anymore really.usually it goes away if you just turn up the volume