This is a term that many biogerontologists have used for a very long time, and informally what they mean by it is the progressive loss of physical robustness that happens with time.

• 这是很多生物老年学家用了很长时间的一个术语，他们非正式地使用“衰老”一词的含义是：充沛的体力随时间而前进性丧失。