Bryan Johnson Spent Millions Building His Anti-Aging Protocol. Now He’s Giving You 6 Free Tests to Measure Your Biological Age at Home

Tracking biological age doesn’t have to drain your bank account.

Bryan Johnson, the tech entrepreneur who has spent millions optimizing his body and claims to be “the most measured person in human history,” recently shared seven simple tests anyone can do at home to estimate their biological age. Six are completely free, and the seventh costs just $20.

The tests provide a snapshot of how your body is functioning compared to your chronological age—and might reveal you’re biologically younger or older than your birth certificate suggests.

Here’s what Johnson and his team discovered when they put these assessments to the test.

Why Biological Age Matters More Than Chronological Age

Johnson emphasizes a crucial distinction between the two types of aging. Chronological age is simply how long you’ve been alive. Biological age represents how well your body actually functions.

What we’re trying to do here is build intuition around the difference between a chronological age and a biological age. A chronological age is the duration you’ve lived on this Earth, your biological age is a representation of your function.

To demonstrate, Johnson enlisted Lauren, a newly hired team member who just completed her PhD in molecular detection. At 30 years old chronologically, she would serve as the perfect test subject to see how these simple assessments reveal biological function.

Test #1: Continuous Push-Ups

The first assessment measures upper body strength and muscular endurance through standard push-ups. For a 30-year-old woman, average performance is eight continuous push-ups. Anything above 16 falls into the “excellent” category.

Proper form matters tremendously here. Arms should be shoulder-width apart, chest must touch the ground at the bottom, and elbows must fully extend at the top. Sloppy technique inflates numbers without accurately reflecting true capability.

Lauren crushed this test with 40 consecutive push-ups—equivalent to the biological age of an 18-year-old. Her chest was “on fire” afterward, but the result spoke volumes about her functional fitness.

Test #2: Sit-Rise Assessment

This deceptively simple test evaluates lower body strength, flexibility, and balance. Starting from a standing position, the goal is to sit cross-legged on the ground and then rise back up without using hands, knees, forearms, or elbows for support.

The scoring system works like this:

• Start with 10 points
• Subtract 1 point for each body part used for support
• Subtract 0.5 points for any unsteadiness

Lauren executed both movements flawlessly, earning a perfect 10 out of 10. Johnson noted that while she made it look easy, most people struggle significantly with this assessment. The ability to sit and stand without assistance becomes increasingly difficult with age and reflects fundamental strength needed for daily activities.

Maintaining a score of 8 or above should be a long-term goal as the decades pass.

Test #3: Sit-And-Reach Flexibility

Hamstring and lower back flexibility play critical roles in injury prevention, fall risk, and overall fitness. This test requires a measuring tape positioned at the 15-inch mark where your feet rest.

With legs straight and extended, you reach forward as far as possible, holding the furthest position briefly. For a 30-year-old woman, average performance reaches 19 inches on the measuring tape.

Lauren achieved 21.75 inches, surpassing the average benchmark and maintaining her perfect streak. Three tests down, three excellent scores.

Test #4: Eyes-Closed Single-Leg Stand

Balance serves as a powerful predictor of all-cause mortality, particularly for people over 41. This assessment challenges you to stand on one leg with eyes closed for as long as possible.

The non-standing foot wraps around the calf of the supporting leg, arms remain at your sides, and the timer starts when your eyes close. For a 30-year-old woman, average performance is 17 seconds.

Lauren’s three attempts produced increasingly impressive results: 29 seconds on her right leg, 18 seconds on another attempt, and a remarkable 1 minute 33 seconds on her left (non-dominant) leg.

I wonder… That’s my non-dominant leg too.

All three attempts exceeded the average threshold, with her final try demolishing expectations.

Test #5: Reaction Time And Reflex

Processing speed slows with age, and this decline appears more pronounced in women than men. Quick reactions reduce accident risk and reflect cognitive sharpness.

Johnson’s team used a smartphone app called “Reaction Time and Reflex Test” with a game mode called “Lights Out.” Five lights appear on screen, and you must lift your finger the instant they disappear. The app records response time in milliseconds across five trials.

Lauren’s best score registered at 0.259 seconds (259 milliseconds)—an excellent result for her age group. Johnson noted that reaction time naturally lengthens with age, making baseline measurements valuable for tracking future changes.

Test #6: Waist-To-Height Ratio

Many experts prefer waist-to-height ratio over BMI for assessing body composition because it more accurately reflects visceral fat—the dangerous fat surrounding internal organs.

The calculation is straightforward: divide waist circumference by height. Both measurements should use the same units (inches or centimeters). The target ratio is below 0.5.

For accurate waist measurement, find the narrowest point between ribs and hips in a relaxed state. Avoid sucking in your stomach.

Lauren measured exactly 60 inches tall with a 28.5-inch waist, producing a ratio of 0.48—comfortably below the 0.5 threshold. Six tests completed, six excellent results.

Test #7: Grip Strength (Requires $20 Dynamometer)

The only test requiring equipment, grip strength assessment needs a hand dynamometer available on Amazon for approximately $20. This measurement correlates strongly with overall muscle mass, functional capacity, and longevity.

For a 30-year-old woman, average grip strength registers around 62 pounds of force. Scores above 91 pounds qualify as off-the-charts exceptional.

Lauren admitted feeling less confident about this test but decided to “be angry” and give maximum effort. Her first attempt produced 84 pounds—already well above average. Her second try reached 85.4 pounds.

On her third and final attempt, Lauren exploded to 96 pounds of grip force, shattering the exceptional threshold.

I didn’t think it could get that high… for me personally.

Johnson acknowledged that Lauren represented an exception rather than the rule. Most people won’t score in the excellent range across all seven assessments.

Building Your Baseline For Improvement

Johnson emphasized that these tests don’t provide comprehensive health assessments. Blood work, advanced imaging, and metabolic testing offer deeper insights. However, these seven measurements create an accessible entry point for understanding biological age.

The real value emerges when you establish baseline measurements and track improvement over time. Disappointing initial results shouldn’t discourage anyone—they simply identify areas requiring attention.

Getting your baseline measurements allows you to assess where you’re at in life, and then it’s the fun game of trying to improve yourself incrementally.

The most important metric isn’t how you compare to others, but whether you’re improving compared to your previous self. These tests democratize biological age tracking, removing the financial barrier that prevents most people from accessing expensive laboratory assessments.

Whether you score like Lauren or struggle with several tests, you now have concrete data points. That information transforms vague health goals into specific, measurable targets you can systematically pursue.