Walking
The cheapest medicine we undervalue
Description
The most-cited piece of health advice in the modern world — that adults should walk 10,000 steps a day — was invented in 1965 by a Japanese company called Yamasa Tokei Keiki, which sold pedometers. The marketing slogan for their flagship product, the Manpo-kei, translated roughly as “ten-thousand-step meter.” The number was chosen because the kanji character for 10,000 resembled a person walking. The company picked it because it sounded ambitious enough to motivate purchase but achievable enough that customers would use the device. There was no clinical research behind the figure. The number entered global public-health communication in the 1990s, was incorporated into the World Health Organization’s physical-activity guidance in the 2000s, and remains, in 2025, the most repeated specific number in the world’s conversation about exercise.
The research that the figure should have been based on, but was not, has accumulated over the past two decades. The largest single study, a 2019 analysis of 16,741 women conducted by I-Min Lee at Harvard’s School of Public Health, found that mortality benefits from walking accumulated up to about 7,500 steps per day and then leveled off. A 2022 meta-analysis pooling data from over 47,000 adults across multiple countries reached similar conclusions, with the optimal range for adults under sixty between 8,000 and 10,000 steps per day and the range for older adults between 6,000 and 8,000. The 10,000 number is not wrong, in the sense that walking 10,000 steps will not damage anyone. It is wrong in the sense that the number was made up by a pedometer company and that the actual evidence supports a wider, lower, and more flexible range.
The deeper story of walking as a medical intervention is more interesting than the slogan suggests. Walking is, by most measures, the single most evidence-based form of physical activity ever studied. It has been shown to reduce all-cause mortality by between 15 and 40 percent depending on the population, to lower the risk of cardiovascular disease, type-2 diabetes, certain cancers, and dementia, to improve mood and sleep quality, and to do all of this at essentially no cost and with almost no risk of injury for healthy adults. The accumulating body of research on what walking actually does to the body has been one of the more striking confirmations in modern preventive medicine of what older traditions had always claimed about the value of regular movement.
The question we’re asking: where did the 10,000-step rule actually come from, what does the research say about how much walking matters and why, and what has the science of walking made visible about preventive medicine?
What we’ll see: the Japanese pedometer marketing campaign, the Lee study and its implications, the physiology of why walking works, and what the evidence suggests for ordinary practice.
Table of contents
01A pedometer company and a number
The Manpo-kei pedometer was launched by Yamasa Tokei Keiki in 1965 as part of a marketing campaign timed to the 1964 Tokyo Olympics. The 10,000-step target was chosen by the marketing team with input from Yoshiro Hatano of Kyushu University of Health and Welfare, who studied physical activity but had no clinical research to justify the specific number.
The figure spread through Japanese health culture in the 1970s and 1980s and migrated to Western public-health communication in the 1990s. The CDC included it in informal guidance. The WHO recommendations of the 2000s referenced it. By 2014, when the iPhone introduced its step-counting Health app, the 10,000-step target had been integrated into the operating system of one of the most widely used consumer devices in the world. The number had become infrastructure.
02The Lee study and what the dose-response curve actually looks like
The Lee study, formally titled “Association of Step Volume and Intensity With All-Cause Mortality in Older Women,” was published in JAMA Internal Medicine in 2019. The methodology was unusually strong for an observational study of physical activity. The participants — 16,741 women with a mean age of 72 — wore research-grade accelerometers for seven days, producing objective step counts rather than the self-reported data that earlier studies had relied on. The follow-up averaged 4.3 years, with 504 deaths recorded during the observation period.
The results showed a clear dose-response relationship between step counts and mortality, but the curve flattened at a level well below the 10,000-step recommendation. Women who averaged 4,400 steps per day had a 41 percent lower mortality rate than women who averaged 2,700 steps. The protective benefit continued to increase as step counts rose, but the rate of additional benefit declined sharply above 7,500 steps. The curve essentially flat-lined between 7,500 and 10,000, with no additional mortality benefit detectable beyond that range. The intensity of the steps — whether the women walked slowly or briskly — turned out to matter less than the total volume.
03What walking does to your body
The mechanism by which walking produces these outcomes has been one of the more productive areas of preventive-medicine research over the past two decades. Walking, unlike most other forms of exercise, engages a particular combination of systems that the body appears to be specifically adapted to. The human skeletal structure, the cardiovascular system, and the metabolic regulation that the body operates under at moderate effort all seem to function at their best when the body is moving at walking pace for sustained periods. The evolutionary argument — that humans are walking animals, that we spent most of our species’ history moving on foot for many hours per day, and that our physiology is built for that activity — has accumulated substantial supporting evidence.
The cardiovascular effects are the best documented. Regular walking improves the elasticity of arterial walls, reduces resting blood pressure, lowers LDL cholesterol, and reduces inflammatory markers. The cumulative effect on cardiovascular disease incidence is substantial. The meta-analyses place the relative risk reduction at between 20 and 30 percent for regular walkers compared to sedentary controls, with the effect appearing at modest activity levels and remaining stable across the higher ranges.
04What survives, and what the evidence suggests
The walking research has produced an unusually clear consensus among preventive-medicine researchers. Walking is the single most evidence-based form of physical activity. The benefits are large, the risks are minimal, the equipment requirements are essentially zero, and the activity is sustainable across the lifespan in ways that most other forms of exercise are not. The specific 10,000-step target is not necessary to capture most of the benefit; substantial gains begin to appear at much lower activity levels, and the curve flattens earlier than the slogan implies. The actionable advice, in the current evidence base, is that any sustained increase in daily walking produces measurable health benefits, with the largest marginal gains coming from moving sedentary individuals to moderate activity.
05Conclusion
Yoshiro Hatano continued to publish on walking until his death in 2019 and acknowledged in later interviews that the 10,000-step figure had been a marketing decision. The Yamasa company continues to manufacture pedometers, although the market has been displaced by smartphone health apps. The target has continued to operate as the dominant cultural framing for daily walking, even as the scientific consensus has shifted toward a more nuanced and lower-threshold recommendation.