Hydrotherapy increases blood circulation, including circulation of the immune system’s white blood cells. It also increases the body’s production of endogenous opioid peptides, particularly endorphins. Enhanced circulation and increased endorphins strengthen the immune system, reduce inflammation, heal injured tissue, improve well-being and energize the body. 

Hydrotherapy also supplies fresh nutrients and oxygen to injured tissue and helps with the removal of waste products. In injuries alternate applications of heat and cold accelerate healing by improving blood vessel integrity and muscle tone. Heat causes peripheral (surface) blood vessels to dilate or expand. Cold causes peripheral blood vessels to constrict and drives blood back to the organs.