While multisport athletes often assess fitness through demanding tests like timed swimming, maximum weightlifting, or functional threshold power (FTP) measurements, Bryan Johnson, a 48-year-old tech entrepreneur known for his obsession with longevity, proposes a simpler, less strenuous method to gauge the body's aging level.

At Business Insider's The Long Play event on 14/4 in San Francisco, Johnson introduced the one-leg balance test, a proxy indicator that helps determine if a person's biological age aligns with their chronological age.

To perform the test, one needs only a stopwatch and enough space to stand on one leg with eyes closed. The test procedure is as follows: Start the stopwatch, close your eyes, and stand on one leg; then measure the time you can maintain this posture before losing balance. According to Johnson's scale: if you can only hold for 0 to 7 seconds, your body is equivalent to an age of 60-80; 7 to 15 seconds corresponds to an age of 40-60; and if you achieve 15 to 30 seconds, your body is in the condition of someone aged 20-40.

"As we age, the brain tends to shrink, gradually diminishing our ability to maintain balance. That is why falls in older adults often lead to very serious health consequences," the entrepreneur explained.

Tech millionaire Bryan Johnson. Photo: Blueprint

Johnson's assertion aligns with scientific consensus. A small-scale study on individuals over 50 years old by Mayo Clinic, published in 2024, showed that among functional tests, the ability to balance on one leg was the indicator most significantly affected by the aging process. Researchers at Mayo Clinic noted this is "a valuable measure of an individual's frailty, level of independent living, and risk of falls." However, this study did not focus on individuals under 50 and did not provide specific data to directly correlate balance time with biological age as Johnson proposes.

The balance test is not a new concept. Cleveland Clinic advises that it is not a comprehensive balance assessment and "is far from a perfect indicator of longevity." Nevertheless, by Johnson's standards, many may find reassurance if their test results, especially on their dominant leg, still reflect the physical condition appropriate for their age.

Bryan Johnson is a prominent tech millionaire, entrepreneur, and investor from the US. He is also passionate about improving health and extending lifespan, investing in biological research projects to slow aging and enhance life quality. Johnson has sparked debate by adopting extreme methods such as high-dose nutritional smoothies, red light therapy, and even injecting his son's blood plasma for rejuvenation.

Binh Minh (According to Business Insider)