Normal aging results in the loss of few nerve cells. Short- term memory may decline, but overall cognitive skills remain. After age 50, there is a slow decline in the ability to hear higher frequencies, and the lens of the eye does not accommodate as well. Loss of skeletal muscle mass is common but can be controlled through exercise. Bone density declines, which can be slowed by adequate calcium intake and exercise.
Females undergo menopause and are no longer reproductive.
In males, sperm production continues until death. Good health habits started when young slow the aging process and contribute to a long, healthy life span.