Harvard researchers have determined that earbuds like those included with iPods and most other MP3 players can be dangerous to pacemakers and defibrillators due to the magnets in them disrupting the pace, causing them to skip a beat or even shut down. The earbuds (not the cords) must come within 1.5" to have this effect, which seems pretty likely to happen at some point.

So, what to do? Were you planning to get Grandma an iPod for Christmas and now have to change plans? Take heart.

While I'm sure they're out there, I've never met anyone over 50 who actually likes earbuds. They're not usually as comfortable as on-ear or over-ear models, and earbuds are also harmful to the eardrum itself. Really, earbuds are to be avoided whenever possible with rare exceptions.

So if you're going to get Grandpa an iPod, get him a nice set of over-ear headphones. I personally recommend the Genius GHP-05 Live DRD 3D Surround Premium Stereo Headphones, but many nice options exist if you're on a budget. These headphones have at least an inch radius of plastic surrounding the magnet, greatly reducing the possibility of heart damage.

So go ahead and help Grandpa rock on this Christmas. It'll make his heart happy.