The increased buoyancy (opposite to gravity) allows for more exercise than is permitted on the land. Increased water temperature and hydrostatic pressure promote increases in circulation and flexibility and decreases in swelling. Hydrostatic pressure supports and stabilises the body, which affects heart and lung function. Increasing speed turbulence and active surface area can all be used to increase exercise difficulty. Improvement of patient morale is another benefit of aquatic therapy. Confidence can be established by providing a positive medium in which to function.