Many people with OA find that a lot of exercise causes pain, but that the joints stiffen up badly if kept still for too long. For most people with OA the best advice is little and often. For example, do the housework or gardening in short spells, interrupted by short rests. Avoid sitting in one place for too long, get up and stretch the joints from time to time. Activities which cause prolonged severe pain are probably best avoided, a pain killer taken before you start may help.
Some people find swimming a good way of exercising and keeping fit, without causing a lot of pain.
Warm water usually relaxes muscles and joints and soothes pain allowing the joint to move more freely. Local warmth from heat lamps or hot water bottles often relieves pain and stiffness of osteoarthritic joints. There are also many applications available at chemists for rubbing into painful joints. Most of these also cause local heat. None of these measures makes any long-term difference to the disease, and most only cause temporary relief of symptoms.