Bones shrink as people age due to osteoporosis and because the cartilage between vertebrae shrinks over time, according to the University of Arkansas for Medical Sciences. Osteoporosis occurs when less calcium is converted to bone and this tissue becomes weaker. With a bone fracture, such as a spinal or hip break, an individual can become shorter.
Daily Mail explains that humans lose up to 0.3 inch per decade in height, starting around age 40. By the age of 80, men can be as much as 2 inches shorter, according to Daily Mail. Women lose as much as 3 inches over time. When the human body ages, its ability to convert calcium into bone slows. Bones shrink slightly when this process occurs. Gel-like discs in between the vertebrae of the spine become compressed as a human ages, which can also lead to shrinkage, according to Kids Health.
One way to prevent bones from shrinking is to eat a well-balanced diet and to exercise. Kids Health reveals foods high in calcium such as tofu, green leafy vegetables and milk can help prevent bone loss. Regular exercise keeps bones strong as well. Smoking and drinking can make osteoporosis worse. Because of gravity, the human body naturally shrinks a little every day; but the body regains its normal height after several hours of sleep, Daily Mail explains.