Aquatic exercise is a low-impact activity that takes the pressure off your bones, joints and muscles. Water offers natural resistance, which helps strengthen your muscles. You can even do aquatic exercise if you don't know how to swim.
You might start with water walking. In water that's about waist-high, walk across the pool swinging your arms like you do when walking on land. Avoid walking on your tiptoes, and keep your back straight. Tighten your abdominal muscles to avoid leaning too far forward or to the side.
To increase resistance as your hands and arms move through the water, wear hand webs or other resistance devices. Water shoes can help you maintain traction on the bottom of the pool.