1. Make pauses
It is always good to have enough pauses and to stretch your muscles throughout the day. You could even install an application to remind you to take a break regularly – or to bring up stretching instructions. While on the phone, you can walk in a small circle in your office. The trashcan and printer should ideally be located at a walking distance.
All in all, make sure that you stand up at least once every hour, even if it is only for a minute of not sitting down.