Ageing and exercise

As for the back, it is the palace of that which is in the chest.When the back is curved and the shoulders drop, the palace will soon be destroyed. As for the lower back, it is the palace of the kidneys. When [a person ] is unable to turn and to sway, his kidneys will soon be sworn out. As for the knees, they are the palaces of sinews. When[a person] is unable to turn and to sway.his kidneys will soon be worn out. As for the knees, they are the palaces of the sinews. When [a person] cannot [freely] bend and stretch and if while walking he is bent forward and leans[on a stick], his sinews will soon be worn out. As for the bones, they are the palace of a marrow.when [a person] cannot stand for long and if while walking he staggers back and forth, his bones will soon be worn out. Those who are able to [maintain] strength, they live. Those who fail to [maintain] strength, they die.
Yellow Emperor's Internal Classic,from 2nd century BCE

You know you're getting old when you stoop to tie your shoes and wonder what else you can do while you're down there.
George Burns,1896-1996

The hard truth about ageing is that eventually, inexorably, the body begins to fail.Muscles and bones slowly weaken, degenerative disease may start to take hold, simply daily activities such as cooking or dressing ourselves become increasingly difficult.Eventually we may even lose the ability to walk, or at least walk without the risk of failings , as our leg strength and balance deteriorate. For the minority blessed with a robust bodily constitution, this decline may not happen until well into old age. even without conscious efforts to delay it. Yet for most of us. the untended body will fail us sooner rather than later, and to a degree that can make the last stages of life extremely challenging.

Sarcopenia
Part of the mechanism behind this growing frailty is the loss of muscle bulk('sarcopenia'-from the Greek 'sarx'=flesh and 'penia'=poverty) that accompanies ageing-estimated as about one per cent a year after the age of 30 and accelerating with each passing decad(although as well will see this rate of decline can be modified by exercise).
As lean muscle mass diminishes, it is replaced by fat. One result of this is that our basal metabolic rate(BMR) declines because fat uses less energy than lean muscle.Our BMR is the energy (measured in calories) required to keep our core body functions(heart, lungs,nervous system, brain etc.)going at rest even there is no physical activity. This decline in BMR is one of the reasons that most of us steadily put on weight as we age-we continue to eat as we always did while at the same time our bodies are using less energy.
What the Chinese nourishment of life tradition has always known, however, is that cultivating the ageing body with exercise can slow the rate of sarcopenia, maintain strong and effective muscles and reduce the decline in BMR. Modern geriatric medicine is increasingly beginning to mirror this knowledge by viewing what were formerly perceived to be inevitable diseases of ageing as, instead, simply diseases of inactivity.
This is very clearly borne out by research. We now know that our bodies have the capacity to build muscle at any age. Exercise which includes strength(and therefore muscle building) training is also likely to improve BMR and increase appetite. This means we can eat (and enjoy) food more, metabolise it better (reducing the risk of gaining weight) and maximise our intake of nutrients. Regular physical activity has further been show to benefit stamina, balance, physical co-ordination, joint mobility, flexibility, agility, walking speed, physical coordination and metabolism in older people.

Exercise and ageing-the evidence
.Older adults who are physically active have lower rates of coronary heart disease, high blood pressure, strokes, diabetes,colon and breast cancer and better functional health and cognitive function. They are also significantly less likely to fall-an increasingly common occurrence from the age of 65 onwards-with attendant risk of hip and other fractures. And if they do fall, regular weight bearing exercise will have helped strengthen the bones and counter the loss of bone mineral density that occurs with ageing.
.The strongest predictor of reaching the age of 90 among 75 year olds is high exercise capacity.
.As evidence for the importance of maintaining strength and mobility, a study found that among 75 and 80 year olds, those with greater hand grip strength, knee extension strength and faster walking times over 10 meters, had reduced risk of death compared to weaker study participants.
.Among recreational athletes(aged 40 to 81 years) who exercised four to five times a week, there was no significant evidence of decline in muscle mass or strength.
.Frail volunteer 90+ year olds living in nursing homes who undertook eight weeks of high-resistance training found significant gains in their functional mobility, muscle strength and muscle size.
.In sixty-five women of various ages, the basal metabolic rate declined by ten per cent after menopause in sedentary women yet remained unchanged in those who were distance runners or endurance swimmers.
.It is never too late to start.Data from the Jerusalem Longitudinal Cohort Study revealed that,"Among the very old, not only continuing but also initiating physical activity was associated with better survival and function. And in a study of over two thousand Swedish men, those who increased their physical activity levels between the ages of fifty and sixty gained the same reduced mortality benefit as those who had always exercised -though only after they had been exercising for five years.
.So great are the benefits of exercise, that, "In terms of maximal oxygen intake, muscle strength and flexibility, the best preserved 65-year-old may out-perform a sedentary 25-year-old.