Creating actual calendar events in your Outlook (or other email system) will allow you to be sure the time is free and will also remind you to walk away from your desk when the event pops up on your screen. If possible, try to do this every 52 minutes. Setting a timer to remind yourself to return back to your work after 17 minutes is important too!
The most successful time-users were working for a solid 52 minutes, without interruption, and then taking a 17-minute break when they would completely disconnect from their work. This allows the brain to re-energize and get ready for the next working block.