If you are in your 40s or 50s, chances are that you are starting to notice some changes in your body, including muscle loss and diminishing strength, even if you exercise fairly regularly.
Reduced levels of physical activity, increases in sedentary behavior and doing less intense exercise all play a significant role in age-related muscle loss, known as sarcopenia, which is a leading contributor to frailty and loss of independence associated with aging. Loss of muscle begins in your 30s but gains momentum when you hit 50 and accelerates even more rapidly in your mid-70s.
The good news is that muscle loss and loss of strength can be slowed considerably in most cases and even reversed in some, regardless of age or fitness level. A 1994 study even showed that people could gain muscle in their late 90s.