Whenever you can, lean against a wall with your hands flattened against the wall and in such a way that your face is very close to the wall. Then use you hands to push your body away from the wall. Do this two or three times at a stretch.
If there is a pool nearby go for swims as often as you can, swimming is one of the best exercises. Water has a lot of advantages. And if nothing else, a cool dip in a pool is a wonderful stress reliever.