Markers of Aging: How Do You Measure Up?

Markers of Aging: How Do You Measure Up?

Julian Whitaker, MD

Anti-aging medicine isn’t about living forever. It’s about helping you function at peak capacity throughout life, feeling great, and being able to do all the things that make life worth living. It’s about being biologically young, regardless of your chronological age. You know your chronological age, even if you’d rather not admit to it. But do you know your biological or functional age?

Although there is no universally accepted yardstick for biological or functional age, experts have identified several biomarkers of aging that can be measured by a physician. These include muscular strength, exercise tolerance, vision and hearing, blood pressure, vital capacity (lung function), heart size, and laboratory tests of DHEA, glucose, lipids, and creatinine clearance (kidney function).

In this article, I also want to share with you some do-it-yourself tests of functional age. These tests are mostly for fun, so get the family involved and see how people of different ages score.

Reaction Time

If you’ve ever been bested by your children or grandchildren in a videogame, you know that reaction time slows down as we age. To test yours, take the falling-ruler test. Have someone dangle a ruler from the end, holding it at the 12″ or 18″ mark (depending on the size of the ruler). Position your thumb and middle finger about 3″ inches apart at equal distance on either side of the bottom of the ruler (the 0″ mark).

As the other person drops the ruler, without warning, catch it between your thumb and finger as quickly as possible, and note where you caught it. Repeat three times and average your scores. Averages generally go from the 6″ mark at age 20-30, to 10″ at age 40-50, and 12″ or more at age 60.

Visual Accommodation

I was in a restaurant recently when I noticed two couples at an adjacent table passing around a pair of reading glasses. None of them could make out the menu without them. As we age, the lenses of our eyes stiffen and lose their ability to accommodate, or change shape, and this interferes with near vision.

To test your visual accommodation, hold this page at arm’s length and slowly move it towards your eyes until the print suddenly begins to blur. (If you wear glasses for distance, you may use them, but do not use reading glasses.) For the average 21-year-old, the blurring point will be about 4 inches from the eyes; at age 30, 5″ inches; at 40, 9 inches; and at 50, 15 inches. By the time you’re 60, your arms probably aren’t long enough to bring it into focus at all!

Skin Elasticity

One of the most visible markers of aging is the skin. Loss of connective tissue in the skin contributes to the sagging and wrinkling that are characteristic of aging. A reliable test of skin elasticity is to pinch the skin on the back of your hand between your thumb and forefinger for 5 seconds, then see how long it takes to return to normal.

This will take less than a second for most people under 30, and 2-5 seconds for those ages 40-50. However, by age 60, traces of the skin fold will remain for an average of 10-15 seconds, and by age 70, 35-55 seconds.

Static Balance

Static balance is the process by which we maintain an upright posture while standing. Age-related changes in the complex interplay between sensory, nervous, and motor systems are one reason why older people are more prone to falling. When your eyes are closed, the differences in static balance between young and old are exaggerated (older people are more dependent on vision for balance), so this test is one of the most dramatic of all biomarkers.

Stand on a hard, uncarpeted floor, barefoot or in low-heeled shoes. Close your eyes and, bending at the knee, lift one foot (the right foot if you are right-handed, the left if you are left-handed) about 6 inches off the ground. Do not move or hop about to maintain your balance – just stand there with your eyes closed. (Have someone nearby to time you and help you if you start to fall.) See how long you can stand on one leg before putting your foot back down. Repeat two more times and average your scores. The mean score at age 20 is 30 seconds; at age 30, 25 seconds; age 40, 15 seconds; age 50, 10 seconds; age 60, 7 seconds; and age 70, 5 seconds.

Lung Function

Lung function also declines with age. There are several tests of lung function, but one you can do yourself is the match test. Light a match and hold it about 12 inches from your mouth. Inhale deeply, and with your mouth open wide (do not pucker up as you normally would to blow out a candle) attempt to blow out the match. Bring the match forward gradually and repeat until you are able to extinguish the flame. Most 20- to 30-year-olds can do this at a distance of more than 10″ from the mouth. For ages 40-50, the average is 7-8″, and for 60-70 years, it is 5″ or less.


  • Have fun with these tests, and remember that the results are only broad indicators of where you are right now. Record your results today, make a concentrated effort to improve your overall health, then take these tests again in six and 12 months. Don’t be surprised if, despite the passage of time, your functional age gets younger.
  • Call (866) 944-8253 or click here to find out how a visit to the clinic can put you back on the path to optimal health and rejuvenation.
  • You may also want to read my book, Shed 10 Years in 10 Weeks, which outlines a step-by-step anti-aging program. You can order it from the Whitaker Wellness Institute at (800) 810-6655.


Modified from Health & Healing with permission from Healthy Directions, LLC. Photocopying, reproduction, or quotation strictly prohibited without written permission from the publisher. To subscribe to Health & Healingclick here.

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