“Running ruins your knees and causes arthritis.”
Strong confidence for recreational running. Systematic reviews do not show higher knee-osteoarthritis prevalence in recreational runners and often find lower prevalence than in sedentary controls. This does not mean every running dose or every painful knee is harmless.
For most recreational runners, running does not inevitably wear out healthy knees or cause arthritis. Prior injury, competitive high-volume exposure, body weight, biomechanics and symptoms can affect individual risk.
Osteoarthritis is influenced by age, genetics, prior joint injury, muscle strength and body weight, not simply by the number of impacts. Pain during running deserves adjustment and assessment, not a universal ban.
Safety note: Existing injury, swelling, locking, instability, rapidly rising training load and some inflammatory or structural joint conditions require a more individualized approach.
Talk to a healthcare professional if: Seek assessment for persistent or worsening pain, swelling, locking, giving way, inability to bear weight or pain after a significant injury.
If running is comfortable and you enjoy it, current evidence does not support stopping solely to protect against knee arthritis. Build load gradually and respond to persistent symptoms.
Increase duration, frequency or intensity one variable at a time, include recovery and strength work, and reduce or modify load if pain is worsening rather than following a rigid percentage rule.