Swimming is an excellent way to exercise for any age and ability.
Swimming offers something no other aerobic exercise does: the ability to work your body without high impact to your bones and muscles. When the human body is submerged in water, it automatically becomes lighter. If you are immersed just to the waist your body bears only 50% of your weight. Sink to your neck and let the water bear up to 90% of your body weight. This also means that the pool provides an ideal place to work stiff muscles and sore joints.