Like beauty, the measure of health changes with time while the essence remains the same. No one is ugly who is intelligent, poised, courteous, neat, stylish, confident and sensitive. So too, no one is unhealthy who is agile, alert, clean, lithe, lean, moderate in behaviour and discriminating in taste.

Unhealthy people, like ugly people, are crude in manner and appearance; excessive in everything that they are and do. Ugliness feeds on itself, hiding and demeaning whatever beauty lies within. So too, poor health is suffocating, and leads inexorably to ill-health. Unhealthy people may show no sign of disease today, but their tomorrow's are severely limited. Poor health does not only shorten life, it diminishes it.

Unhealthy people often like to think that they are living life to the full - an excess of everything and every action to excess. And as far as their lives are concerned they are probably right since they use up their limited potential is a shorter space of time. The point that they recklessly ignore is that their potential for living is limited: a half-gallon jug cannot hold a gallon of wine. Herein lies the myth of "intense" pleasure; the lie in the "high" from using cocaine. This is the pathology of manic behaviour that is ultimately a form of depression.

Health is sublime, and its own reward. Health living is effortless and timeless, which is not to say that it does not require effort and good timing. Health does not decline with age or restraint. The value of good health lies in its appreciation, and appreciation grows with wisdom which only comes with age. Truly has it been said that good health is wasted on the young., who abuse it and take it for granted. Good health in old age is the greatest of fortunes, but like any real fortune, it cannot be acquired overnight. It must grow on a solid foundation.

We are almost all born with an amazingly solid foundation and we remain capable of growing in strength and ability until the very last moments of our lives. But from the very first year of life, it seems we are determined to be as unhealthy as we can. We remain peculiarly susceptible to the notion that the right way is the easy way, probably because long-term benefits often require short-term sacrifices. Who wants to go out and exercise in the morning when it so much easier to take a tablet and convince ourselves that we feel more energetic.

And so it is that health is ultimately an attitude; a willingness to strive; "wellness" in thought and deed. Good health is far more than a medically sanctioned "clean bill". To consider oneself healthy because a physician can find nothing that needs fixing is to court disaster. The important difference between a man and a machine that is lost in our preoccupation with physical wholeness, is that human parts improve with use. The less you use your lawn-mower, the longer it will last. The more often you cut your lawn, the longer you will last.

A single sentence can sum up the essential requirement for a healthy life: use it or you will lose it. There is no human faculty that does not improve with its employment - or that will not deteriorate with disuse. Be it our physical strength, our mental agility, our spiritual fortitude, our social skill, our volition or our ambition, without regular and committed engagement, it will surely wither and render us increasingly vulnerable to the vicissitudes of time and chance.

Most of all, a healthy person is one who does not give up. Never say die and you will live until you have no more life to live; stop trying and you will be dead long before it is time to lie down in your grave.