Disease

Health is the state of physical and mental well-being. It is broader than simply being free from a diagnosed disease. Physical health can affect thoughts, feelings and participation in everyday life, while mental ill health can affect sleep, appetite, activity and physical well-being.

A disease disrupts the normal functioning of an organism. Diseases can affect humans, other animals and plants, but they do not all arise or spread in the same way. One fundamental distinction is whether a disease is communicable or non-communicable.

A person who has no diagnosed disease is therefore not necessarily in good health. For example, they might still be experiencing severe stress, poor nutrition, social isolation or mental ill health. Equally, someone living with a long-term disease may manage it successfully and retain good well-being in many parts of life.

Health describes a person's physical and mental well-being. It is therefore broader than whether a named disease has been diagnosed. Someone's health may be affected by their genes, environment, lifestyle, an infection or physical trauma, and physical and mental health can affect one another.