Pets provide their owners (or "guardians") both physical and emotional benefits. Walking a dog can provide both the human and the dog with exercise, fresh air and social interaction. Pets can give companionship to people who are living alone or elderly adults who do not have adequate social interaction with other people. There is a medically approved class of therapy animals, mostly dogs or cats, that are brought to visit confined humans, such as children in hospitals or elders in nursing homes. Pet therapy utilizes trained animals and handlers to achieve specific physical, social, cognitive or emotional goals with patients.