By Jen Murphy

How fast you can run a mile and the number of push-ups you can crank out aren’t just good for fitness bragging rights. They’re indicators of how well you’re aging.

You could be 48 but bike, ski or lift weights like you’re 38 or 58. For a best-case scenario, think of an athlete like football star Tom Brady at the top of a young man’s game well into his 40s.

Having an idea of your so-called fitness age matters. You can slow various declines in health through relatively minor changes, say academics and health professionals. Cardiovascular changes, for example, have been shown to add years to your life.

The first step is to track your fitness benchmarks in areas such as aerobic capacity and muscular endurance. Then, you should aim to keep them in an optimal range to help manage your aging, says Dr. Randall Espinoza, associate director at the UCLA Longevity Center. (You can try some sample tests below.)

While there is no universally agreed-upon way to measure fitness age, a true road map to longevity should also consider diet, consistent and adequate sleep, and maintaining social ties.

The VO2 max factor

As the body ages, balance, strength and cardiorespiratory fitness decline, sometimes beginning as early as our 30s.

The term “fitness age” has been used in exercise circles for about 20 years. The number was initially based on your VO2 max, a measure of your maximal aerobic capacity.

Experts consider the VO2 max a critical piece of longevity data. The American Heart Association has argued that it should be considered a vital sign that’s regularly measured by doctors, just like your blood pressure.

Research suggests your VO2 max will decline by roughly 10% per decade through earlier adulthood and up to 15% per decade after age 50. But if you do the right kind of cardio exercise throughout your life, one case study suggests that it’s possible to have the VO2 max of a 35-year-old when you’re 80.

Espinoza notes that sedentary adults need not aspire to become athletes. A 2018 study found that going from bad to good cardiovascular fitness yields more benefits than going from good to great.

Other benchmarks matter

The definition of fitness age has broadened. Having the aerobic fitness of someone half your age is great. It still won’t help you get up from the ground if you fall.

A more complete assessment of how well your body is aging also considers strength, power, muscular endurance and balance, says Michael Crandall, a certified strength and conditioning specialist at E by Equinox gym in New York City’s Hudson Yards.

Crandall says we can perform many measures of fitness at home or in a gym with little to no equipment. Below are four tests he suggests to try. Some are pass-fail. Other test scores are more specific and can be compared with scores for people your gender and age.

Don’t get discouraged if your numbers are subpar. These tests are meant to provide motivation—and for those who score well, an affirmation that efforts in the gym are paying off.

Aerobic fitness: 12-minute run or 1-mile walk

Fitness-age calculators and apps provide a ballpark estimate of your aerobic capacity. The most precise way to measure VO2 max happens while wearing a mask that covers your mouth and nose: You walk or run on a treadmill, under a health expert’s supervision, until you can’t continue.

A do-it-yourself version of the test was developed by Dr. Kenneth Cooper, founder of the Cooper Institute in Dallas. Participants see how far they can run in 12 minutes and use this conversion to calculate their VO2 max and corresponding fitness ranking based on age and gender.

Cooper’s son, Dr. Tyler Cooper, president of Cooper Aerobics in Dallas, cautions that this test is intended for healthy, active people.

For people who are more sedentary or who experience joint pain from running, he recommends the Rockport Walk Test. It requires participants to walk a mile as briskly as possible while wearing a heart-rate monitor and use this conversion to calculate VO2 max and fitness ranking.

Upper-body strength: Push-up

The push-up measures how well you can move your body weight, Crandall says. To perform, start in a high push-up position, with hands just outside of your shoulders. Lower until your arms are bent past 90 degrees.

You can place a yoga block at its lowest height beneath your sternum to ensure you lower yourself far enough. Compare your total number of push-ups with good form with this chart.

Core muscular endurance: Side plank

Muscular endurance is what allows you to go for a long hike or carry your suitcase up a flight of stairs without getting winded. Just like muscle mass and strength, your muscular endurance declines with age.

To test your core’s muscular endurance, perform a side plank with your feet stacked, knees locked out and one elbow on the ground.

If you can hold it with good form for more than 45 seconds, you’re above average. Between 20 to 45 seconds is good. If you can’t maintain proper form for 20 seconds or more, you need to work on your core strength, regardless of age or gender.

Mobility and stability: No hands get-up

We sit and rise from the floor with ease when we’re young. That can get tougher with age. Performing this movement confidently is key to quality of life in our later decades.

This is a pass-fail test. Sit on the floor with bent knees near a wall or chair, in case you need help. Roll onto your left hip so your knees fall to the left. Shift your weight so your shins stack above your knees. Step your right foot forward into a low lunge. Step your left foot to meet the right as you rise to stand. Reverse the motion. If getting up with no hands is too difficult, work toward getting up using one hand.