When the Beatles contemplated turning 64, they worried whether someone would still be sending them a Valentine, birthday greetings, bottles of wine.

When I turned 64, I worried about my "biological age," as measured in how long I could stand on one foot and whether I could sit down on the floor and get back up without using my hands.

That's because in recent years there have been a slew of at-home tests that purport to tell you how well you're aging compared to your peers, whether your body is older or younger than what the calendar says, even how long you're going to live.

When I was a kid, I took the Presidential Fitness Test, commonly conducted in public schools back then. Now I frequently take any "predictor of all-cause mortality" or DIY longevity assessments that I come across.

Here's just a few examples:

  • "Doctor explains how to do a simple physical test that can predict your longevity," reads a headline describing something called the sitting-rising test. "People who fail are more likely to die in six years," the Upworthy article helpfully adds.
  • "Scientists link increased risk of early death to a simple test," is the way the U.S. edition of the Independent news site described seeing how long you can stand on one leg. The so-called flamingo test "reveals your likelihood of dying within 7 years," according to the New York Post.
  • "Handgrip strength can predict risk of death," according to an orthopedic surgeon's YouTube channel. The doctor's video cited a study that showed about 40% of men 65 and older who had a handgrip strength of less than 22 kilograms "were no longer alive 5 years later."

I click on these things because my attitude is not dissimilar to Woody Allen, who once said: "I'm not afraid of dying. I just don't want to be there when it happens."

Here's what happened when I tried some of these at-home tests to see how long I've got.

The sitting-rising test

How to do it: In bare feet, try to sit on the floor and then get back up without using your hands, knees, forearm or side of the leg as a support. A 2012 Brazilian study of more than 2,000 people ages 51 to 80 found that the people who had the most difficulty doing this were more likely to be dead six years later.

My experience: Sometimes I can do this pretty well. I haven't had to use my hands or knees, but I may have used the side of my foot and wobbled quite a bit. That would result in some deductions from my score by a test evaluator. I got better after I worked on my technique, but I also lost my balance and nearly crashed into an end table.

A pro's take: Dr. Teresa McCarthy, a geriatrician and associate professor at the University of Minnesota's Center for Healthy Aging and Innovation, cautions against older adults taking this test without supervision.

"Falls are the way bad things happen," McCarthy said. In fact, she added, I might have decreased my life expectancy if I fell and broke my hip while trying to test my life expectancy.

One-legged stance test

How to do it: In your bare feet, stand on one foot with the other foot off the ground and placed on the back of the opposite leg. Keep your arms by your side. See if you can do this at least 10 seconds. A 2022 study of more than 1,700 people ages 51 to 75, again by Brazilian researchers, found that even adjusting for age, sex and underlying conditions, those unable to balance for 10 seconds had an 84% higher risk of death within 10 years.

My experience: I practice my balance by brushing my teeth while standing on one leg, so I got bored after timing myself after 90 seconds.

A pro's take: McCarthy assesses frailty and falling risk in older patients by using a different test, the Timed Up and Go, or TUG test. Even so, she cautions that one test doesn't tell the whole story. "It's not causality. It's not because your walking speed is slow, you're gonna die," she said. Again, she cautioned against a balance test if there's any chance of injury. "Don't fall. Just don't fall," she said. "It's not worth it."

Grip strength

How to do it: Several studies suggest that grip strength is a way to predict overall strength and overall health. "Grip strength is an accurate predictor of all causes of mortality in middle-aged and elderly persons," according to one Japanese study of nearly 5,000 people ages 35 to 74. Experimenters test grip strength using a squeezable device called a hand dynamometer.

My experience: The most expensive hand dynamometers can cost several hundred dollars, so I had doubts about the accuracy of the $40 one I bought on Amazon.com. It came with a chart showing "typical measurements for healthy individuals." I was only able to get a middling number for a man my age. However, I tried a different test recently suggested by the Times of London: the dead hang, or seeing how long you can hang from a pull-up bar. I was able to hit the goal the Times suggested for people in their 20s and 30s (between 60 and 90 seconds).

A pro's take: McCarthy cautioned against reading too much into this test. Squeezing a racquetball until I have forearms like Popeye won't increase my life span, she said.

Facial aging

What is it: National Geographic recently reported that researchers are trying predict biological age by using AI to analyze a 3-D image of a person's face. The process is called a "facial aging clock." Researchers are also exploring using AI-analyzed images of the tongue to estimate biological age, according to the magazine.

My experience: Novos, a longevity testing and supplement company, offers what it bills as a free online AI facial age test. You send in a picture of your face, and the company emails you a report. I tried it twice. In one case, it said my facial age was 55. With another picture, it said I looked 58. I got good scores on facial wrinkles, average on eye bags, but not so hot on skin pores.

A pro's take: My personal physician, Dr. Magdalena Kappelman, an internal medicine and pediatrics specialist with M Health Fairview, said she's skeptical. She's not read of any good science that links a young face with good health. I guess I'll hold off on Botox.

Online questionnaires

What is it: There are sites where you answer a host of questions about your exercise, diet, family history, social life, stress levels, sleep habits, whether you spend time in nature, whether you meditate, how much you stimulate your mind, how much pollution is around you and more. Then an algorithm spits out a report on how well you're aging, plus advice on how to live longer.

My experience: The results can be contradictory. According to Tally Health, my lifestyle is "very healthy," with a score of 91 out of 100, and scores in the 90s for mental health, diet and sleep. But it ranked my fitness as only 71 out of 100. On the other hand, a fitness age calculator by the Norwegian University of Science and Technology took my height, weight, resting pulse and activity level, and then congratulated me for having a body that's only 39 years old.

The Living to 100 Life Expectancy Calculator gave me a surprisingly precise prediction: "You're going to live for 27 more years!" But it suggested I might add three months to my life if I cut down on the amount of caffeinated tea that I drink. And a longevity quiz by Novos gave me a healthier-than-average score of 78 out of 100, but suggested I sit too much and could benefit from the antioxidants in a cup of coffee or two a day.

Biological age tests

What is it: Several companies offer consumers an estimate of their "biological age" based on a cheek swab sample or a small blood sample. These epigenetic tests are supposed to tell you how well your cells, tissues and organs are aging.

My experience: The $250 cheek swab test by Tally Health said my "TallyAge" is one year and three months less than my chronological age. I guess that's better than being told I'm a well-meaning elderly man with a poor memory. But I could be doing even better, the company said, if I signed up for a membership plan that included more tests and supplements that cost $129 a month.

A pro's take: The "epigenetic clocks" that these sorts of tests are based on "are not validated in longitudinal studies to predict anything about an individual's health or likelihood of aging poorly or healthfully," according to Dr. Paul Robbins, co-director of the Institute of Biology of Aging and Metabolism at the University of Minnesota Medical School. He said different tests will often yield different results for an individual. "Thus, the results from one specific epigenetic test cannot be assumed to provide much information about health or aging." Kappelman suggested that I save my money.

The takeaway: Get an annual exam

But Kappelman isn't bothered by my interest in these tests.

"I love talking about them, because it opens the door to preventative health care" discussions, she said.

Trying to see how long you can stand on one leg or measuring your grip strength gives some information, she said, but cautioned not to read too much into a single test.

"Any one of them is like taking a single variable and predicting something really complex," Kappelman said. "It probably only gives kind of a partial picture, because the process of aging is so complicated and there's so many things that factor into it."

While she admits these biomarker self-assessments "can be interesting and something to talk about," she adds, "I don't want somebody at home to do one of these tests and then lose sleep over it."

They are no substitute for an annual checkup, where she listens to my heart, checks my cholesterol and blood pressure, talks about cancer screenings, stress levels and ways I can have a healthy life — not just a long life.

"Please come back and see me every year," she said. "There are helpful things that we can do."