Swimming offers something no other aerobic exercise does: the ability to work your body without harsh impact to your skeletal system. When the human body is submerged in water, it automatically becomes lighter. When immersed to the waist, your body bears just 50 percent of its weight; dunk yourself to the chest and that number reduces to around 25 to 35 percent; with water all the way to the neck, you only have to bear 10 percent of your own weight. The other 90 percent is handled by the pool.
This means that the pool provides an ideal place to work stiff muscles and sore joints, especially if you're overweight or suffer from arthritis.
In its recommendation for the right types of exercise for people with arthritis, the Arthritis Foundation suggests those that stretch muscles, those that strengthen muscles, and those that provide an aerobic workout. A few laps in the pool combine all three!
If the pool is heated, so much the better for arthritis sufferers, as the warm water can help loosen stiff joints. In fact, people with rheumatoid arthritis receive greater benefits to their health after participating in hydrotherapy than with other activities. It's also been proven that water-based exercise improves the use of affected joints and decreases pain from osteoarthritis [source: CDC].