Don't do that. As I'm using the Mail app in Windows 8, the mail notification will pop up immediately after the server receive it. In other words, if someone send you an email, you will see the mail popup immediately. The thing about the mail app on Windows and Windows Phone is that they use push to get the mail. Basically they only pull the content of the mail without any details like headers, thus prevent the data leaking. However, this will consume the battery a lot. I suggest you keep those important inbox, like 2 or 3 mailboxes, for about 15-30 mins and those are not important for 1h to manually. That way you can maximize the battery life.