Inclusion Criteria:  Normal or corrected-to-normal vision Able to speak and read Chinese Scores of Mini-Mental Status Examination >= 25 Physical Activity Readiness Questionnaire score < 0 Able to conduct the exercise with moderate intensity Meet the criteria to undergo magnetic resonance imaging Provide informed consent  Exclusion Criteria:  Diagnosed or self-reported cognitive problems (e.g., mild cognitive impairment or dementia) Diagnosed or self-reported physical disease (e.g., untreated hypertension and chronic heart disease, stroke, brain tumor, musculoskeletal disorders, other exercise contradictions) Diagnosed or self-reported major psychiatric illness (e.g., major depression, schizophrenia) Diagnosed or self-reported neurodegenerative disease (e.g., Alzheimer's disease and other dementias, Parkinson's disease (PD) and PD-related disorders, Huntington's disease) History of alcohol or drug abuse History of chemotherapy Traveling consecutively for three weeks or more during the study Unwillingness to be randomized to one of the two groups Currently participating in another study trial  Exclusion Criteria for functional magnetic resonance images (fMRI):  Participants will be excluded if s/he has a contraindication to fMRI scanning, such as aneurysm clip, implanted neural stimulator, cochlear implant, any implanted device, cardiac pacemaker. To ensure volunteers are eligible for the current project, they will be asked to fill out a questionnaire to inform whether they have conditions (e.g. paralyzed hemidiaphragm) or present unnecessary risks (e.g., pregnancy) during the recruitment period.