Standing on one leg serves as proxy for neurological health

Entrepreneur Bryan Johnson, 48, has introduced a straightforward balance exercise as a proxy for biological age, suggesting that physical stability can reveal more than a person's chronological years.

Speaking at Business Insider’s "The Long Play" event in San Francisco on Tuesday, Johnson invited attendees to participate in a simple trial: closing one’s eyes and standing on one leg while timed.

According to Johnson’s metrics, a duration of zero to seven seconds reflects a biological age of 60–80, while 15 to 30 seconds indicates a range of 20–40.

"As you age, your brain atrophies, and your ability to maintain your balance goes away," Johnson explained, highlighting the critical nature of fall prevention in older populations.

His assertions find some support in a 2024 Mayo Clinic study, which identified one-leg balance time as the functional test most significantly affected by ageing in adults over 50.

Researchers described the test as a "valid measure of frailty, independence, and fall status," though they did not provide specific biological age correlations for younger participants.

Despite the accessibility of the test, the Cleveland Clinic has voiced caution, noting that while balance is important, this exercise is "far from a perfect indication of longevity" on its own.

It should not be considered a comprehensive evaluation of overall health. Johnson, who has gained international notoriety for his multi-million-dollar "Project Blueprint" longevity regime, continues to advocate for quantifiable metrics to track human ageing.

He remains focused on his goal of reversing his own biological age through rigorous data-driven lifestyle interventions.