The science
Walking speed turns out to be one of the most informative things about you that nobody measures.
Not because walking is special in itself, but because it takes almost everything working together — muscle, balance, vision, attention, the brain routing all of it. That makes it a summary. Here is the research footing is built on, each finding with the population it was actually found in.
The finding that matters most in midlife
At 45, the slowest walkers had been aging five years faster.
5.0 years
In a New Zealand birth cohort followed for five decades, 904 adults had their walking measured at age 45. Those in the slowest fifth had been aging — measured across nineteen biomarkers spanning multiple organ systems — about five years faster between ages 26 and 45 than those in the fastest fifth.
Found in adults measured at age 45 — a population finding, not a prediction about any individual
Rasmussen LJH, Caspi A, Ambler A, et al. Association of Neurocognitive and Physical Function With Gait Speed in Midlife. JAMA Network Open. 2019;2(10):e1913123.
The same study found a difference of about sixteen IQ points between the slowest and fastest fifths, and linked slower walking to smaller total brain volume. Most striking: signs of it were visible in these people’s neurocognitive assessments at age three. Walking speed at midlife appears to summarise a lifetime, not just a leg.
The evidence, with its boundaries
Every finding belongs to a population.
A result found in 73-year-olds is a result about 73-year-olds. Stretching it over everyone is the most common way health claims go wrong, so we print the population next to the finding every time.
| Study | What it found | In whom |
|---|---|---|
| Rasmussen et al. JAMA Netw Open, 2019 | Adults with the slowest walking at 45 had been aging about five years faster since their twenties, scored roughly sixteen IQ points lower, and had smaller brain volume. Signs were detectable in childhood assessments. | 904 adults, measured at age 45 Dunedin birth cohort, New Zealand |
| Skillbäck et al. Alzheimer’s & Dementia, 2022 | Among people who were cognitively healthy at the start, walking slowed measurably up to nine years before any cognitive change was detectable. Wider literature puts the lead time at seven to twelve years. | 287 adults, followed from age 70 for 15 years Gothenburg H70 cohort, Sweden |
| Studenski et al. JAMA, 2011 | Faster walking speed was associated with longer survival, across nine pooled cohorts — the study that made walking speed a recognised vital sign. | 34,485 older adults, mean age 73.5 Validated in 65+ only. We do not apply it below 65. |
| Callisaya et al. JAMA Netw Open, 2022 | Decline in walking speed and memory together was associated with higher dementia risk than decline in either one alone — which is why footing measures both rather than one. | Older adults Community-dwelling cohort |
All four are observational studies. They establish that these things travel together in populations. None of them establishes that walking faster causes better outcomes, and neither do we.
Honesty
What we don’t claim.
Any health product can find studies to point at. The useful question is what the studies don’t support, so here is ours.
The research measured walking in clinics. We measure it with a phone.
The findings above come from instrumented walkways and supervised timed walks. footing reads the motion sensors in a phone in your pocket. We believe that tracks the same underlying thing — that’s the entire bet — but demonstrating how closely is work we’re still doing, not work that’s finished. Until it’s published, treat a footing number as a well-founded estimate rather than a clinical measurement.
The survival evidence is about people over 65.
The best-known result in this field — walking speed predicting survival — was found in adults with a mean age of 73.5. It is genuinely powerful evidence, and it is evidence about older adults. If you’re 48, that study is not about you, and we won’t quote it at you as though it were.
An association is not a mechanism, and a population is not a person.
People who walk slowly at 45 were, on average, aging faster. That does not mean walking faster would have slowed their aging, and it does not mean any particular slow walker is aging quickly. footing tells you where you sit in a distribution. What that means for you specifically is a conversation with a clinician, not an app.
The cohorts are narrower than the world.
The midlife study was 93% white and drawn from a single New Zealand city. The nine-year lead-time study followed 287 Swedes. These are careful studies with real limits, and reference data built mostly on white Western populations may fit some people better than others. Building a broader normative picture is the point of the research contribution we ask about — and never require — when you start.
footing does not diagnose anything.
Not dementia, not Parkinson’s, not concussion, not fall risk as a clinical determination. It is a general wellness tool and not a medical device. If your numbers move in a way that worries you — or if anything else about your health does — the right next step is a clinician, and footing will say so rather than trying to be one.
From the Journal
The same evidence, at reading length.
Essays on movement, cognition and aging — written from the research this page cites.
How a phone measures your walk: inside your movement signature
The same sensors that count your steps can read the finer texture of how you move. Here is what they capture, why your walk is so personal, and how that data should be treated.
Balance, steadiness, and staying fall-resistant as you age
A fall can look like bad luck, but steadiness is something the body builds and can lose gradually. The way you walk quietly tracks it, and much of it can be trained.
What your gait reveals about fatigue and recovery
Long before you feel wrecked, tiredness starts to reshape how you move. Your walk, and your run, can hint at when to push and when to back off.
Credibility is the whole product.
A measurement you can’t trust is worse than no measurement. We would rather show you a smaller, honest number.