Keep some tennis balls in a desk drawer and squeeze one in each hand as hard as you can for 10 second bursts. This is a great exercise to do when you have been typing for too long. Take those same tennis balls and roll them around under your feet (taking your shoes off first!) This is almost ridiculously pleasurable! (Tip: keep the tennis balls hidden away and out of reach to prevent them mysteriously disappearing from your office and reappearing in the car, garden or toy cupboard).
Try a five minute resistance band workout. Resistance bands are cheap, easy to store, and effective – and can be used to exercise many different areas of the body. Follow the instructions that come with the resistance band for a quick exercise routine – or try a search on Google for ideas. You can achieve quite a lot in five minutes with these. To try an inexpensive set of resistance bands, click on the amazon link below: