Extensive work in human physiotherapy has demonstrated that a suitably monitored course of hydrotherapy acts by encouraging a full range of joint motion in reduced weight bearing conditions, therefore improving muscle tone & promoting tissue repair, without imposing undue stress on damaged tissues. Controlled swimming helps to improve cardiovascular stamina, muscle tone, range of movement & is particularly helpful in aiding recovery from injury or surgery whilst also improving general fitness, especially in the management of obesity. Muscle wastage begins within three days of any immobilisation so to prevent further weakness or injury it is important to rebuild, through safe exercise, any muscles that have deteriorated. It is better to treat dogs in heated water since cold water causes constriction of the blood vessels near the skin to the superficial muscles (just under the skin) which restricts the flow of blood making the muscles less efficient.