Health is even more difficult to define.
Just as illness has many dimensions, so too health can be seen and even assessed across many dimensions, each necessary for the completeness of the other. If disease is essentially about the disturbance of equilibrium, then health can be defined as a state of equilibrium. But this equilibrium by its very nature cannot be static. The human body is constantly in a state of flux both within and without. It has to constantly adapt to challenges from outside, challenges that are not just physical but, in a human being at least, also psychological. Besides like any other body, the human body too must have its own rhythm, which is primarily an extension of the animal rhythms. The difference however is that an animal seldom disrupts his rhythm and therefore there is little need for an internal adaptation. But with human beings the natural instinct is replaced by a conscious or rather half-conscious volition. We do not eat simply because we are hungry, we do not sleep simply because we are sleepy or tired; we do not even mate simply because it is the season and the moment for mating. Other factors have been added apart from instinct, such as pleasure, social pressure, job requirements, monetary considerations, other over-riding interests and so on and so forth. The internal rhythms have therefore been completely disrupted and this has surely taken a heavy toll upon the body. Given this constant state of flux it is difficult to define a perfect state of health for a human being. The complexity becomes even more complex when we understand that the human body (and the mind as well) is endowed with a lot of reserve. A seemingly healthy body may be just on the edge of a serious disruptive event simply because it has reached its end reserves. And this can deceive even an expert eye.
An example to illustrate this is of a 75 year old man who consulted a well-known cardiologist. Looking at his test results the cardiologist declared that his heart is as young as a teenager’s. The man was dead within a week due to a massive heart attack! It is because of such cases that the concept of stress-tests evolved. The reverse is perhaps even truer. Grim pronouncements and prognostications of imminent death may never come true. The author personally knows of an instance where a lady underwent depression because her physician pronounced that she had another six months to live. Well, she lived on for at least fifteen years before dying of something quite unrelated. As an aside her physician died before her!
Thus we have not only a physical but also a psychological and emotional component of health, even a social health and of course as is being recognized now, a spiritual aspect of health as well. It is quite possible and indeed it is being increasingly seen that one dimension can influence and over-ride the other altogether. A smoker may never die of the ill-effects of smoking and a person doing all the right things may die young. The reason is not just genetic predisposition but something deeper, thereby making any simplistic assessment of health in a human being futile.
Besides, unlike the animal, a human being is not made of one type and each individual has his or her own unique rhythm making the task even more complicated. Nevertheless, following the cues so far, we can say that health is a state of balance and harmony within and without. It is a state wherein the forces of integration and harmony are in the ascendant and it is reflected not only in our physical functioning but even more so in the way we think and feel and react and respond to our environment, in our lifestyle and attitudes, to say the least.
The human body has to adjust to a host of challenges within and without. To begin with each organ of the body responds to certain movements of thought and emotions, desires and impulses. And since each is interlinked with the other and the energy feeders are the same, an overuse of one organ would necessarily be at the expense of the others. Similarly an under-use of an organ system may lead to its progressive atrophy which will, in its turn disturb the balance of the rest since there is a complex interdependence of each system on the other. However much we may specialise, the human body is one and a disturbance in one part sooner or later, in however minute or big way, begins to reflect upon the other systems. In childhood or youth, it is possible to recover this lost harmony and balance relatively easily since in general the forces of growth and harmony are more active. But with growing age, for a variety of reasons, this general balance is changed in favour of the forces of disintegration and a relatively small disharmony can swiftly snowball into a rapidly downhill course for the body.
Not only within, the human being has to also face the challenge of harmonising with its complex environment. Like the animal, it has to face challenges of physical environment which it tries to do both by internal resources and also by external manipulation. This in turn adds to the challenge in the long run for with each technological substitution there is a corresponding biological amputation of some capacity that nature has provided. Secondly, and unlike the animal and plants, the human being has to adapt not only to his own fairly complex internal processes but also the complex psychological and social stresses and environing forces that arise from his interaction with other fellow human beings. Whether we consciously register it or not, whether our present scientific equipment record it or not, the human body does receive and retain in its obscure memory the imprints and impacts it receives not only from its physical but also its psychological environment. That is why, certain memories can trigger a whole set of chain reactions.
An additional stress for adaptation arises from the environing life around us. From the micro-organism to the macro animals, from the impact of radiation to the daily pollutants, the human organism has to accommodate and compete with a variety of separate units. So long as the body is able to adapt successfully things work out well and we can reasonably say that we are in a state of health. This is a dynamic process and it changes from moment to moment.
Thus, a state of health may be defined as a state of dynamic equilibrium both within and without, internally between one organ and another, externally between the organism and other organisms.