August 16, 2017
Why You Shrink As You Age

Why You Shrink As You Age

by Berkeley Wellness  |  

Do you know how tall you are? Many people, especially older ones, think they’re taller than they really are. Sometimes it’s wishful think­ing, but often it’s lack of awareness of the shrinkage that almost always comes with aging. In a French study, for instance, researchers measured 8,600 women over 60 and found that they overestimated their height by an inch, on average, and had lost about 2 inches from their tallest recalled height.

No one wants to shrink, of course, but it’s a normal part of life if you live long enough. Here are five things to know about shrinkage—and what you may be able to do to prevent it.

How much do people shrink as they age?

Estimates vary, but on average people lose ¼ to ½ inch every decade after age 40 or 50, with losses increasing in later years, and women generally losing more than men. Research from the Baltimore Longi­tudinal Study of Aging, for example, found that women lost an average of 2 inches between the ages of 30 and 70 (and just over 3 inches by age 80). Men lost a little more than 1 inch by age 70 (and 2 inches by 80). But averages hide wide variability: Some people lose an inch or more in a single decade, some shrink only after age 60 or 70, and a few don’t shrink at all.

Why do we shrink?

People lose height because the discs between the vertebrae in the spine dehydrate and compress. The aging spine can also become more curved, and vertebrae can collapse (compression fracture) due to loss of bone density (osteoporosis). Loss of muscle in the torso can also contribute to stooped posture. Even the gradual flattening of the arches of the feet can make you slightly shorter.

Is losing height an indicator of health problems?

It can be, which is one reason why your health care provider should measure your height, usually as part of a periodic health exam. Height loss is especially worrisome if it is largely the result of a compression fracture or other skeletal conditions. Such frac­tures can cause back pain and limit mobility, though often there is no pain or other symptoms. And the same loss of muscle that con­tributes to shrinkage can also contribute to back pain. Moreover, the greater the shrinkage, the greater the risk of hip and other non­vertebral fractures. Several studies have found that people over 65 who lost at least 2 inches in the past 15 to 20 years were at signifi­cantly higher risk for hip fracture than those who shrank less; one study found the increase in risk was greater in men.

Loss of height can also be related to a host of metabolic and physiological changes that may have a negative impact on health. Or height loss may simply be a marker for poor health in general or poor nutrition. But don’t despair: Many people with markedly diminished stature remain perfectly healthy.

Certainly, if you have any concerns about your loss of height, especially if you have chronic back pain, discuss this with your health care provider.

What height should older people use to calculate their BMI—current or maximum height?

You should probably use your current height, but experts dis­agree. Body mass index, or BMI, is a formula that evaluates weight relative to height, with higher results generally indicating more body fat. If you shrink and your weight stays the same, your BMI will go up, which may shift you from, say, the healthy weight category to overweight. Thus, a woman who is 5 foot 3 inches tall and weighs 150 pounds has a BMI of 26.6, in the low-middle end of “overweight,” but if she shrinks to 5 feet tall and weighs the same, her BMI will increase to 29.3 (obesity starts at 30). If older people shrink largely because of spinal compression and loss of bone and muscle but stay the same weight, then body fat must account for the difference—so it makes sense that their BMI increases (along with waist circumference).

On the other hand, some studies suggest that being overweight (but not obese) after age 65, based on BMI, is not unhealthy, which may indicate that the increase in BMI caused by shrinkage is mis­leading. In that case, a slightly higher BMI due to loss of height wouldn’t matter. Keep in mind that despite the precise numbers it produces, BMI provides only a rough estimate of “fatness” and health risks for an individual.

Can you do anything to prevent or reduce shrinkage?

It’s largely out of your control, since genetics plays a big role, as do things you did in the past—for instance, how much bone you built when you were young. But even in later years you may be able to slow shrinkage by taking steps that will help protect your bones and muscles—such as doing weight-bearing exercise; consuming adequate calcium, vitamin D, and other bone-healthy nutrients; not drinking alcohol to excess; and above all not smoking. For example, an older Belgian study published in Gerontology found that people who did moderate aerobic exercise throughout their lives shrank less than those who were sedentary all their lives or who stopped exercising after age 40.