Assertion Supported AI assessment confidence: 95% certainty 3/5 debate potential 2/5

Bryan Johnson's single-leg balance test benchmarks for determining biological age

Bryan Johnson · Bryan Johnson’s Best Health Hack: Lower Your RHR Before Sleep = Sleep Better and Live Longer · Oct 14, 2025 · at 2:15

This episode carries Bryan Johnson's own address, with nobody on the show putting questions to them. It still counts as said, and it is kept out of every score on their page.

Bryan Johnson, founder of the Don't Die longevity movement, presents biological age categories based on performance in an eyes-closed single-leg balance test at the All-In Summit.

0:00 / 0:14exact quote · 14.5s

▶ Watch the full episode on YouTube → 720p mp4 · rendered on demand · StarZero watermark

“So, if you are, ah, between 15 and 30 seconds, that's roughly age 20 to 40. Seven to 15 seconds, you're between 40 and 60, and zero to seven, you're 60 plus. As an age category, ok?”

quote is from the automated transcript, cleaned for reading: filler sounds and stutters are removed, nothing is rephrased. names can be misheard (the analysis reads context, assessments check outside sources). how →

The claim, plainly

Holding an eyes-closed single-leg balance for 15 to 30 seconds corresponds roughly to biological age 20 to 40, 7 to 15 seconds corresponds to age 40 to 60, and 0 to 7 seconds corresponds to age 60 and older.

a quote alone can be ambiguous, so this restates it with the references and context of the conversation around it resolved. AI-written; the tape below the player is the source.

Assessment

Bryan Johnson's statement closely reflects established clinical norms and benchmarks for the eyes-closed Unipedal Stance Test (UPST). Multiple clinical studies and public health reference targets (e.g., Springer et al. 2007, El-Kashlan et al. 1998, and UK BMJ reference targets) establish that average eyes-closed balance times are ~15 to 20.7 seconds for ages 20-39/40, ~8 to 13 seconds for ages 40-59, and ~1 to 4 seconds for ages 60 and older. These empirical ranges directly map to Johnson's rough age brackets of 15-30s (age 20-40), 7-15s (age 40-60), and 0-7s (age 60+).

Springer et al. (2007) published normative best-trial scores for eyes-closed stance: 18-39 years averaged ~15.0s, 40-49 years averaged ~12.7s, 50-59 years averaged ~8.3s, and 60-69 years averaged ~4.4s.
UK Health and BMJ reference targets for eyes-closed single-leg stance set benchmarks at ~15s (under 40), ~8-13s (aged 40-59), and ~3-4s (aged 60-69).
El-Kashlan et al. (1998) reported mean eyes-closed stance durations of 20.7s for ages 20-49, 6.1s for ages 50-59, and 2.0s for ages 60-69.

Checked against

[1] nih.gov [2] sralab.org [3] eacefitness.com [4] thepelvicpt.com [5] sralab.org [6] rbwm.gov.uk [7] eacefitness.com [8] missouri.edu

eyes closed single leg balance test age norms seconds "Springer" "2007" "unipedal stance test" "eyes closed" mean time age groups eyes closed unipedal stance test norm values age "unipedal stance test" "eyes closed" "18-39" "40-49" "50-59" "60-69" "70-79"

assessed as of 2026-07-30

This assessment is an AI reading of a public statement, made against the cited references with the confidence shown. It can be wrong. The quote, the tape and the references are all on this page; if something is off, use report an error below. full disclaimer →

Mentioned

biological age eyes-closed balance test

⚑ Spot an error? Report it

More from Bryan Johnson

Assertion Not checkable as stated

Bryan Johnson: Gerber IP-blocks heavy metal test results outside California

“Yeah, I think the four, four big. And so it's like, okay, so go to Gerber's website, I can't find heavy metals results anywhere. And then I realized my VPN's on, and I'm coming from a server outside of California, they've IP blocked.”

Bryan Johnson Apr 3, 2025 ▶ 1:41:43 All-In Live from Austin: Colin and Samir, Chris Williamson, and Bryan Johnson

Assertion Not checkable as stated

Bryan Johnson: Most All-In Summit attendees have mental health issues

“And if we're honest, the majority of you in this room have some moderate to serious mental health problem.”

Bryan Johnson Oct 14, 2025 ▶ 8:14 Bryan Johnson’s Best Health Hack: Lower Your RHR Before Sleep = Sleep Better and Live Longer

Prediction Not checkable as stated

Bryan Johnson compares his 'Don't Die' movement to major world religions

“Don't die is the next major ideology on par with democracy, capitalism, Christianity, Islam.”

Bryan Johnson Oct 14, 2025 ▶ 10:11 Bryan Johnson’s Best Health Hack: Lower Your RHR Before Sleep = Sleep Better and Live Longer

Assertion Not checkable as stated

Bryan Johnson: Don't Die Certified found high glyphosate levels in diapers

“We looked at diapers. There was a dangerously high level of glyphosate in diapers.”

Bryan Johnson Apr 3, 2025 ▶ 1:39:21 All-In Live from Austin: Colin and Samir, Chris Williamson, and Bryan Johnson

Assertion Not checkable as stated

Bryan Johnson claims he has the best health biomarkers in the world

“Basically, I have the best biomarkers of anybody in the world.”

Bryan Johnson Oct 14, 2025 ▶ 4:43 Bryan Johnson’s Best Health Hack: Lower Your RHR Before Sleep = Sleep Better and Live Longer

Insight

Bryan Johnson: Managing resting heart rate before sleep is the best health habit

“So you guys, the single best thing I've learned out of everything I've ever done is your resting heart rate before sleep is the best thing you can do for your health.”

Bryan Johnson Oct 14, 2025 ▶ 5:55 Bryan Johnson’s Best Health Hack: Lower Your RHR Before Sleep = Sleep Better and Live Longer

Bryan Johnson's single-leg balance test benchmarks for determining biological age

More from Bryan Johnson

Turn any episode into a week of clips.