You must walk 10,000 steps a day to be healthy.

Analysis

The number 10,000 originated with the Japanese pedometer 'manpo-kei' ('10,000-step meter') marketed in 1965. It was a memorable round figure rather than a finding from a controlled trial.

Recent meta-analyses of accelerometer studies in adults aged 60+ show mortality risk continues to fall up to roughly 6,000–8,000 steps per day and then plateaus. Younger adults plateau closer to 8,000–10,000 steps. The marginal benefit beyond the plateau is small relative to the gains made between 2,000 and 6,000 steps.

The engine flags this as Refuted in its categorical form ('must walk 10,000') because the claim asserts a hard threshold, while the underlying evidence supports a graded dose-response with a lower inflection point. A softer phrasing — 'more daily steps are associated with lower mortality' — would resolve as Supported.

Sources Weighed

• JAMA Internal Medicine, Lee et al. (2019)
  Peer-reviewed cohort study
  Found mortality benefit plateauing near 7,500 steps in older women.
• Lancet Public Health, Paluch et al. (2022)
  Meta-analysis
  Pooled cohort data showing age-dependent step-count plateaus.
• Manpo-kei marketing materials (1965)
  Primary historical document
  Origin of the '10,000 steps' figure, not a clinical source.