Among participants with high NfL concentrations (>25 pg/mL), those who engaged in medium physical activity (<150 minutes per week) had a 12% slower rate of global cognitive decline (SD units, or β, –0.065; 95% CI, −0.099 to −0.032) and participants who engaged in high physical activity (≥150 minutes per week) had a 36% slower rate of decline (β, –0.048; 95% CI, −0.080 to −0.016) than did participants with low physical activity (no reported participation) (β, –0.075; 95% CI, −0.108 to −0.041). Here, NEFL is linked to Mental deterioration.