['We aimed to determine whether there was a relationship between lifestyle factors and Alzheimer disease biomarkers.', 'In a cross-sectional study, we evaluated self-reported histories of recent and past cognitive activity, self-reported history of recent physical activity, and objective recent walking activity in 186 clinically normal individuals with mean age of 74 ± 6 years. Using backward elimination general linear models, we tested the hypotheses that greater cognitive or physical activity would be associated with lower Pittsburgh compound B-PET retention, greater (18)F-fluorodeoxyglucose-PET metabolism, and larger hippocampal volume, as well as better cognitive performance on neuropsychological testing.', 'Linear regression demonstrated that history of greater cognitive activity was correlated with greater estimated IQ and education, as well as better neuropsychological testing performance. Self-reported recent physical activity was related to objective exercise monitoring. However, contrary to hypotheses, we did not find evidence of an association of Pittsburgh compound B retention, (18)F-fluorodeoxyglucose uptake, or hippocampal volume with past or current levels of cognitive activity, or with current physical activity.'] Does cognitive activity relate to cognitive performance but not to Alzheimer disease biomarkers?