What is the study of health and the observance of health rules called?

The study of health and the observance of health rules is referred to as hygiene. Hygiene encompasses practices and conditions that promote health and well-being, targeting the prevention of illness and maintenance of cleanliness. It involves understanding how personal cleanliness and sanitation affect individual health and the health of the community.

The focus on health rules in hygiene covers essential aspects like handwashing, food safety, and environmental sanitation, which are crucial for preventing infections and chronic diseases.

While nutrition deals with the intake of food and its effects on health, and healthcare pertains to the broader system that provides medical services, hygiene specifically targets the practices that help maintain health through cleanliness and proper living conditions. Public health, although related and vital for community health, is more focused on protecting and improving the health of populations through organized efforts, rather than emphasizing individual health rules and practices.