Does pedometer drain the battery?

My 5G nano is about three months old. It doesn't seem to hold charge well, so I searched online and found Apple's page that tells how to test battery life (basically, charge the unit fully and let it play until it quits). I did that and after 10 hours it still said it had about 60% charge. That's good, but not at all what I usually get. Normally I use the nano when working out -- either jogging or on an elliptical machine, and I get about 5 hours of battery life. When I tested the unit per Apple's instructions, it was lying completely still -- and got LOTS more battery life. The only difference? In my normal use, it's getting jiggled a lot (and the pedometer isn't even on!).

So it seems to me that continuous jostling of the unit causes the pedometer mechanism to drain the battery much faster, even with the pedometer not turned on. 😟

Anyone else experience this?