Inclusion Criteria:  For PwD,  confirmed diagnosed of mild to moderate-intensity dementia cognitive impairment as indicated by a HK-Montreal Cognitive Assessment (Hong Kong version; HK-MoCA) score of 8-19 to indicate mild to early moderate dementia will be recruited  For family caregivers  live together with the PwD identify as the primary family caregivers of the PwD  Exclusion Criteria:  engaging in > 60 minutes per week of moderate or more vigorous exercise in the previous six months acute muscular-skeletal problem, stroke or cardio-respiratory disease.