The October issue of Real Simple magazine quotes a Microsoft and University of Illinois at Urbana-Champaign study that claims it takes 17 minutes “for a worker interrupted by e-mail to get back to what she was doing.”
If this statistic is true, and I know from experience that there is a refractory time after any distraction, it is strong evidence against leaving the notification alert active on your e-mail program. Instead, you should schedule time in your day to check your e-mail. Based on the type of office environment you work in, you might need to check your e-mail at the top of every hour. However, most people can get by only checking their e-mail two to four times during the work day.
I also recommend checking e-mail during the times when you are usually distracted during the day. Whether this is when others tend to interrupt you or when your mind typically wanders on its own, it’s best not to try to do high-functioning activities when you plan to work through your e-mail inbox. For me, this is right after lunch when I find it difficult to concentrate for more than a few minutes at a time. I check e-mail, return phone calls, and do a little bit of filing.
Try turning off the notification alert on your e-mail system and only checking e-mail on a schedule and see if it improves your productivity. If the interruption refractory period really is 17 minutes, you should immediately notice significant gains in your focus.