Why do you shrink when you get older? Experts explain

Once you become an adult, you typically reach your full height. That's a number that comes up regularly in your life, whether it's at the doctor's office or while shopping for a pair of pants. But your height can change with age, and it's no myth — you shrink with time.

Yep, age-related height loss is a typical part of getting older. People usually lose about a centimeter in height every 10 years after age 40, according to Medline Plus, and that pace of height loss speeds up after age 70. Overall, you can lose between 1 to 3 inches in height as you age, per Medline Plus.

While age-related height loss is normal, there are times when it's a sign of an underlying health condition. Here's what you need to know about getting shorter as you age, as well as when it becomes a potential issue.

Why do you get shorter as you age?

On a macro level, you get shorter as you age due to changes in the bones, muscles and joints. "There are a few different things going on here," Dr. Angela Catic, a geriatrician and associate professor in the Huffington Center on Aging at Baylor College of Medicine, tells Yahoo Life. One, she says, is that the discs between the vertebrae in your spine lose fluid as you get older. "They become dehydrated and, with that, they lose height — and you lose a bit of height," she says.

Abdominal muscles also tend to weaken over time, which can create a stooped posture, causing you to appear shorter, Catic says.

In women, menopause can speed up bone loss "due to the loss of the protective effects of estrogen on bones," Dr. Arashdeep Litt, an internal medicine physician with Spectrum Health, tells Yahoo Life. That, too, can cause you to get shorter.

But height loss can also be due to osteoporosis, a bone disease that develops when bone mineral density and bone mass decreases, or when the quality or structure of bone changes, Litt says. That can decrease your bone strength and increase your risk of fractures, according to the National Institutes of Health (NIH).

How to tell the difference between normal height loss and signs of osteoporosis

Osteoporosis can lead to spinal compression fractures, which are small breaks in the vertebrae of your spine, Catic explains. "In a lot of cases, people don't even realize this happens," she says.

So, how can you know what's behind your shrinking size? Your medical provider should keep track of your height at your routine well visits, and that measurement could indicate a red flag. Your doctor will suspect osteoporosis if you have an overall height loss of 1.5 inches or more, or a height loss of 0.8 inches or more from your last measurement, Litt says. "This much height loss is a sign of osteoporosis and warrants a bone density test," she says.

A bone density test is like an X-ray of your body, and it takes about 15 minutes, according to the U.S. Department of Health and Human Services. The test can tell your health care provider how strong your bones are and will determine if you have osteoporosis, as well as your risk of fractures in the future.

How to prevent height loss

Again, some height loss is normal. But Catic says you can lower your risk of height loss by doing the following:

• Exercise regularly.

• Lift weights (this, along with regular exercise, stresses your bones and makes them stronger).

• Eat a diet rich in calcium and vitamin D to support bone health.

• Avoid smoking, excessive alcohol use and excessive caffeine intake — all of which are risk factors for osteoporosis.

When to see a doctor for height loss

If you feel you're experiencing height loss, it's a good idea to bring it up to your doctor at your next annual exam. And, if you seem to be getting shorter at a fairly rapid rate, bring it up with your doctor sooner rather than later, Catic says. You'll also want to be seen soon if you're dealing with severe back pain or you've developed a stooped or hunched posture, per the NIH, as these can be signs of osteoporosis.

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