和訳困っています＞＜
-Ageing-
As we've seen, many people live healthy, happy and productive lives for many years after the standard retirement age. But sooner or later, barring accidents, we all become old. It used to be thought that ageing was a steady decline in functioning, with people going inevitably downhill from the age of 50 or so. But now we know that is not so. But now we know that is not so. The research evidence which suggested this pattern of ageing was seriously flawed in the way that it was done, and modern experiences show that ageing occurs quite differently.
The general pattern seems to be that we have only a very gradual decline in our older years, and that decline can be slowed down by exercise and activity, but that eventually we reach a period of more rapid physical decline, which rarely lasts for more than about five years. Usually, the person dies at some point during the five-year period. In some old people, that decline is brought about by an accident-a fall or some similar event- which damages them physically but, more importantly, shakes their confidence and makes them feel unable to cope with life as they once did.
How inevitable the decline is, once it has begun, is something nobady knows. We do know, though, that even old bodies can respond surprisingly well to exercises were found to be putting on muscle mass as a result - in other words, their muscles were responding to the exercise and becoming stronger. This finding has been repeated a number of times now, and it shows that the saying " it's never too late " may be even truer than we realize.
The real danger in ageing, more than any other, seems to be the person's own beliefs about it. Someone who expects to decline and become incapable as they grow older is not likely to face their body or mind with extra challenges. Without exercise, our bodies have no incentive to grow stronger or to maintain their normal levels of strength; so they become weaker. This, to the person who expects to be weak as a result of age, is 'proof 'that they were right, and their belief in inevitable decline is confirmed. But really, it began as a self-fulfilling prophecy.
お礼
重ねて御礼申し上げます。 本当にありがとうございました！
補足
冒頭のbtwはおそらby the way(ところで)の略語かと思われますがどうでしょう。 それとご回答ありがとうございました！翻訳機では細かな所までは理解し難いので本当に助かります。