How strong is the evidence for Cycling?

Direct evidence specifically on cycling is comparatively limited: a systematic review reports associations between commuter cycling and lower all-cause and cancer mortality, and a long-running Swedish women's cohort found cycling-test fitness in midlife linked to lower dementia risk decades later. That evidence is currently rated moderate (55/100), built on 4 published studies, including 1 meta-analysis -- a reasonable base, but not yet enough for full certainty.