Bryan Johnson reports short-term metric changes during a five-day high-altitude trip

On 29 September 2026, Bryan Johnson reported spending five days at about 7,000 ft in Colorado and Wyoming. He said sleep fell 15%, a metric he called “nervous system” fell 17%, and resting heart rate rose 16%. On his first night back at sea level, he reported sleep up 13%, the nervous-system metric up 17%, and resting heart rate down 12%. He attributed the rebound to five days of acute hypoxic stress. The posts do not name the devices, define the nervous-system metric, provide raw values or baseline dates, or explain how the percentages were calculated. They give no control period and do not account for travel, exercise, sleep schedule, hydration, illness, or other changes. This is an instrumented-looking, uncontrolled n=1 report. It cannot isolate altitude as the cause or show that the same response would occur in other people. No treatment change or adverse event was reported. The numbers are Johnson’s own measurements and interpretation, not validated clinical outcomes. We preserve the percentages as claims and do not infer a general health effect from them.

“My body slingshotted in rebound from 5 days of acute hypoxic stress.”