Sprint HTC Hero :: Does The Mail App Keep The Phone Awake

alright, my dad's phone (post update) is at 100% awake time. it wasn't pre-update. my phone is also sitting at a higher awake time post update. i first thought the culprit was the mail app running more often. i have to force close it more frequently now. well, my dad complained about his battery again and i checked the awake time. 100%. he also asked me which programs were essential and i told him to kill the mail app. he said he keeps it open all the time cause he uses it all the time. sooo, now it is looking more to me like it is the mail app keeping the phone from sleeping.