The purpose of this study is to determine if a home based physical activity training program for patients with Alzheimer's dementia has effects on clinical and neurobiological parameters.

Inclusion Criteria:

• age >55 years
• German is the dominant language (necessary for neuropsychological testing)
• minimum of 8 years formal school education
• caregiver (e.g. spouse) living at home with participant
• physical examination does not reveal contraindications to physical activity
• stable dose of pharmacological dementia treatment according to German guidelines (DGPPN) with acetylcholinesterase inhibitor or memantin or combination for at least 6 months
• no other medication that could influence cognitive functioning (e.g. benzodiazepines, sleep aids, neuroleptics)

Exclusion Criteria:

• history of neurological or psychiatric disease other than AD
• history of substance abuse disorder
• history of electroconvulsive therapy (ECT) during the last 6 months
• structural brain deficits diagnosed in the MRI scan, also without clinical relevance (incidental finding)
• pacemaker, artificial heart valve, insulin pump or other medical implants
• average steps/day are above 10.000 steps/day