It's the same with any part of your body. If you rarely walk, your legs will become weaker, and if you loll around like a couch potato, they'll atrophy. And if you don't do some sort of exercise, which involves using every part of your body, at least two or, ideally, three times a week, you will eventually become lethargic and feeble. Then you will lose bone density, the flexibility of your joints and muscles will start to go, and after a certain age, you will almost certainly begin to shrink. If you were athletic as a teenager and you continue to be so, you could still be strong and healthy well into your seventies or eighties. At the age of seventy some swimmers can still do their laps or even swim the Channel almost as well as when they were in their twenties. This goes for runners and dancers too. I have a friend in her seventies, Gillian Lynne, the famous choreographer of Cats, among many other shows, whose body hasn't changed one iota since she was twenty. She says the main reason for this is that she has never stopped doing her daily barré exercises and she works with dancers a third of her age.
Now let's get to grips with this aging business to see what can be done about it. If we can't stop the clock, let us at least try to slow it down. Aging is a horrible word, which is all too often used in the most derogatory way by the media -- "wrinkly rocker," "aging actress," etc. It's almost as though it's used to denote total uselessness in a person. You can't help getting older, but you can help yourself from becoming old and infirm, in mind as well as body. In particular you should stop thinking that getting older bars you from the joys and benefits of youthful pursuits, such as sports or socializing.
In the past fifty years the number of people over sixty, many of whom are living extremely productive, happy lives, has practically doubled. The later years can be active and rewarding, and getting sick isn't an inevitable part of getting older. Research on both sides of the Atlantic indicates that self-healing can be achieved through appropriate choices in diet and exercise. With a rapidly aging and increasingly sedentary population in the Western world (the number of people aged sixty and over is projected to increase from 12 million in 2002 to 18.6 million in 2031).
Beating the clock
Osteoporosis and arthritis were once considered an old lady's lot. Lucky enough to live to a ripe old age, she would inevitably become so crippled and disabled that she would be condemned to a life of pain and be unable to take care of herself. Today, by the age of fifty the average woman has lost up to one third of her bone mass. Sadly, osteoporosis will affect one woman in two in later life and in some families the risk is even greater. It's an insidious disease that creeps up over the years. Bones slowly lose their tissue and become weaker and more brittle until they eventually waste away. Until fractures occur, this often goes unnoticed, by which time it may be too late to do anything about it. Although everyone suffers from osteoporosis to some degree, people who smoke and drink excessively, have more than six cups of coffee a day, who hardly ever exercise, and have small bones may be more prone to it and can start to suffer earlier.