Inclusion Criteria:  60 to 79 years of age Having at least one modifiable dementia risk factor Complaints of cognitive decline by a participant or informant A performance score that is lower than 1.0 standard deviations below the age-, and education-adjusted normative means for one or more of the delayed recall, naming, visuoconstruction, attention, and executive function tests MMSE Z score ≥ - 1.5 Independent activities of daily living Being able to use the tablet PC through education, or having a person who can help a participant use the tablet PC. Having a reliable informant who could provide investigators with the requested information Provide written informed consent  Exclusion Criteria:  Major psychiatric illness such as major depressive disorders Dementia Other neurodegenerative disease (e.g., Parkinson's disease) Malignancy within 5 years Cardiac stent or revascularization within 1 year Serious or unstable symptomatic cardiovascular disease Other serious or unstable medical disease such as acute or severe asthma, active gastric ulcer, severe liver disease, or severe renal disease Severe loss of vision, hearing, or communicative disability Any conditions preventing cooperation as judged by the study physician Significant laboratory abnormality that may result in cognitive impairment Illiteracy Unable to participate in exercise program safely Coincident participation in any other intervention trial