An n-of-1, field-derived estimate of physiological age built from hiking movement data — VO₂Max, heart-rate drift, HRV, and recovery — pooled across a session series. A working measure of functional age, not a clinical epigenetic clock.
Trail-Derived Biological Age is TrailGenic's term for an n-of-1, field-derived estimate of physiological age — how old a body functions, rather than how many years it has been alive. Where a clinical biological age relies on a blood draw and a DNA-methylation clock, the trail-derived estimate reconstructs the same question from movement data captured during disciplined hiking under controlled stress.
The estimate is a composite of physiological proxies, each with an independent relationship to aging in the broader literature: VO₂Max — the anchor, and the strongest single physiological predictor of all-cause mortality — alongside heart-rate drift, heart-rate variability, resting heart rate, and recovery response. No single proxy carries the estimate. It is pooled across a longitudinal series of instrumented sessions and recalculated as the series grows. The discipline is in measuring the same way every time, so the record stays comparable to itself.
The number moves only when the underlying physiology improves. Stacked stressors — fasted endurance, altitude, cold, heat, electrolyte stability, nature immersion, and measured recovery — train precisely the markers the estimate reads, which is why a sustained hiking practice can hold functional age below chronological age over time. In TrailGenic's founding record, the figure has pooled to roughly 32–40 against a chronological age of 53 across 20+ sessions.
What it is not: a clinical diagnostic, a DNA-methylation epigenetic clock, or a guarantee of anyone else's result. It is a single-subject, transparently-measured estimate that reflects direction and discipline over time. The canonical claim and its supporting dataset are documented in the Trail-Derived Biological Age science article; the sibling field metric is Trail-Derived VO₂Max.