Health, according to the World Health Organization, is "a state of complete physical, mental and social well-being and not
merely the absence of disease and infirmity." A variety of definitions have been used for different purposes over time. Health can
be promoted by encouraging healthful activities, such as regular physical exercise, and by reducing or avoiding unhealthful
activities or situations, such as smoking or excessive stress. Some factors affecting health are due to individual choices, such as
whether to engage in a high-risk behavior, and others are due to structural causes, such as whether the society is arranged in a
way that makes it easier or harder for people to get necessary healthcare services. Still other factors are beyond both individual
and group choices, such as genetic disorders.
