Have you considered getting one of those big rubber balls to sit on instead of a chair while sitting in front of the computer? It's supposed to increase your core strength and burn calories because you have to balance on it. Just a thought.
anon-e4ddf5ec-924e-4a7d-b587-080cb3939591@cf8ee123-c709-465c-86c9-ce2303edb481.anon and Louise like this comment.