Research has shown that if you suffer from osteoarthritis pain in the knee or hip, then aerobic and stretching exercises in warm water can help to relieve it.
There are three categories of exercises called hydrotherapy, hot water, cold water, ad alternating hot and cold water.
Hot water is known for stimulating the immune system and is also good with increasing your circulation. Cold water constricts blood vessels and is effective in reducing inflammation. Using both, hot and cold has been found to improve circulation.
It was found that water heated to about 32c to 36c slightly reduces osteoarthritis pain over three months.