The Science Behind Why Humans Shrink As We Age

Growing taller is a normal part of becoming older when you are a child, but did you know that shrinking as you age is a normal part of later adulthood? You may have noticed that your grandparents are shorter than your parents, and you may even be taller than all of them. As we get older, we naturally lose inches of our height. In fact, according to NBC News, most people lose a quarter-inch to a third of an inch of height each decade starting at around 40 years old.

There are several reasons why humans shrink in height as we get older. Normal shrinking can be caused by pressure on the spine from holding the body upright. Medical conditions that are common in older adults can also impact height. According to Dr. Pham Liem, a geriatrician at the UAMS Donald W. Reynolds Institute on Aging, "Older adults can get shorter because the cartilage between their joints gets worn out and osteoporosis causes the spinal column to become shorter." (via the University of Arkansas for Medical Sciences). According to the Mayo Clinic, osteoporosis is a condition that causes weak and brittle bones that are often seen in older adults and can cause fractures from even minor injuries. But it's not the only thing that can cause us to shrink during our golden years.

While shrinkage is a natural part of the aging process, there are things that can be done to slow the rate at which we lose height. According to the National Spine Health Foundation, the key components of spine health for aging include good posture, exercise, and practicing good health habits. Avoiding slouching and looking down at electronic devices can help the spine keep an upright position over time. Participating in weight-bearing exercises such as walking, running, and weight training can help build strong muscles, putting less strain on the spine to keep the body upright (via the Mayo Clinic).

Another important part of keeping the spine healthy involves getting the right vitamins and minerals to keep the bones strong. The National Institute of Health recommends including vitamin D and calcium as part of a healthy diet in order to prevent bone diseases such as osteoporosis, which can contribute to spine issues. Without vitamin D, the body cannot use the calcium it ingests, making vitamin D just as important as calcium for bone health.

As previously mentioned, shrinking a couple of inches over time is a normal part of getting older. According to the Baltimore Longitudinal Study of Aging, women tend to lose around two inches off of their height between ages 30 and 70, which increases to 3 inches by 80 years of age. Men lose around one inch of their height during the same time and typically lose another inch by the time they reach 80. 

According to one medical expert, TODAY Show contributor Dr. Roshini Raj, "For men[,] it's less prominent because they have more muscle mass in general and their bones tend to be stronger they lose less height," (via NBC News). Dr. Raj says that if you find yourself losing more inches than normal, it could be a sign of osteoporosis. Per Medline Plus, osteoporosis is a silent disease, so there are not many indicators that you have it. If you believe you may have osteoporosis, your doctor can perform a bone mineral density test to determine the condition of your bone health.