Reference values for volume and intensity of physical activity. Age- and sex-specific centile curves for average acceleration (AvAcc, panels A & B) and intensity gradient (IG, panels C & D) representative of the adult US population. Colouring refers to the dose–response relationship of the respective metrics with all-cause mortality. Green indicates a reduced hazard ratio, whereas red indicates an increased hazard ratio. Reduced hazard ratio is defined as IG: −2.7 to −2.5 and AvAcc: ∼35–45 mg, beyond which no further risk alterations were noted. A version for individuals with colour blindness is available in Supplementary material online, Figure S5.