Hormone changes in men that are related to aging.
Andropause is a term used to describe sex hormone changes in aging men. In particular, the hormone testosterone declines over a period of many years. The consequences of that decline aren't always clear. A man's testosterone level drops about 1% a year after age 40. But most older men still have testosterone levels within the typical range.
In some cases, low testosterone may not cause any symptoms. In others, it may lead to lower sexual desire and activity; problems with erections; breast discomfort; height loss; easily broken bones; and hot flushes or sweats. Symptoms also can include low energy and motivation; depressed mood; sleep problems; lower muscle bulk and more body fat.