Health is the absence of illness, functionally,
as the ability to cope with everyday activities, or positively,
as fitness and well-being. In any organism, health is a structure
of homeostasis. This is a state of balance, with inputs and outputs
of energy and matter in equilibrium (allowing for growth). Health
also implies good forecast for continued survival. In sentient
creatures such as humans, health is a broader concept.
The World Health Organization defines health
as "a state of total physical, mental and social well-being,
and does not consist only of the absence of disease or infirmity."
Using the WHO definition classifies 70-95% of people as harmful.
A deeper inquiry into the definition of "health" reveals
that what makes a cell healthy is sole from what makes an organism
Similarly, what makes an organism healthy is
unique from what makes a population healthy. To illustrate this
point, consider that Japan has the most life expectancy of any
nation (2004 UN Human Development Report), despite having one
of the highest smoking rates, especially among men (2004 UN Human
The most solid aspects of wellness that fit firmly
in the kingdom of medicine are the environmental health, nutrition,
disease prevention, and community health matters that can be investigated
and assist in measuring well-being.