Even if you think you can't dance - get up and shake to the music; if you have arthritis in your knee, dance while sitting. The more you move your body, the more calories you'll burn! Movement will also clear excess sugar and "bad" cholesterol from your blood (I'm told). It will help you to relax and this will lower your blood pressure.
(I'm going to put the laptop down right now, get up and shake to some music! For 30 minutes!)