7th Gen battery drains faster when working out

I have read a lot on battery drain of the 7th gen ipod. I have tried all the 5 R's except the restore so far, but was curious on this issue I am having. My wife complained about her battery being almost dead after she was on a run with it. The run was about an hour and the battery was almost dead. As a test last night, I set the ipod on continuous play at the same volume level she uses and let it sit on the table. After about 4 hours, the battery indicator showed it still was barely under full charge. This was after I reset it, so thought it may be fixed. Today she was working out again and the battery was almost dead again after about an hour and a half of use!

Has anyone else experienced the batter draining faster while working out? Only difference would be when I tested at home, the ipod was stationary and when working out, it is moving.

I will probably try the restore yet and fully drain the battery and recharge, but wanted to see if anyone here finds this odd.

Thank you.