Called the "sixth vital sign" by researchers, usual walking speed predicts survival and functional aging as reliably as many invasive clinical tests — and it's free to measure.
Usual gait speed — how fast you walk at your natural pace — integrates the function of multiple body systems: cardiovascular capacity, muscle strength, balance, neurological coordination, and motivation. A 2011 JAMA study pooling data from 34,485 adults found that usual gait speed predicted survival across all age groups and both sexes.[1]
It's particularly valuable because it requires no equipment, no lab, and takes 30 seconds to measure.
Mark a 4-meter (13-foot) distance on flat ground. Walk at your usual pace. Time it with a phone stopwatch. Calculate: 4 meters ÷ seconds = meters/second.
Repeat 3 times. Take the average. Test every 6–12 months in the same location and conditions.
Meters per second (m/s) — 4-meter walk test
Above 1.0 m/s for adults 60+
Above 1.2 m/s associated with excellent longevity outcomes
Below 0.8 m/s — associated with significantly higher mortality risk
Every 6–12 months; after 90-day protocol completion
Reference ranges vary by lab, age, sex, medication status, and clinical context. Use these as discussion prompts with your clinician — not as diagnosis.
Both metrics independently predict longevity and together reveal the cardiovascular + muscular picture.
The other key functional longevity measure. Together with walking speed: a complete functional aging picture.
Take the Stack Analyzer — 6 questions to a personalized measurement path, protocol, and supplement stack.