Alzheimer's disease (AD) is a neurodegenerative disease leading to one of the most common forms of dementia in humans and memory disorder is one of the first symptoms that lead to diagnosis.

Present in greater amounts in the regions of the hippocampus and cortex, the Brain-derived neurotrophic factor (BDNF) is essential to both learning and memory processes. This protein is found in lower amounts in people with AD. Acute physical activity of moderate to vigorous intensity would increase the levels of plasma BDNF whether for a healthy person or a person with AD. Nevertheless in rest, healthy people have higher level of BDNF than individuals with AD. There are no studies on the effect of chronic exercise based on BDNF level at rest in people with AD. In a hypothetical endurance training of 18 sessions, whether interval or continuous training the levels of BDNF would increase in people with AD at rest. Their physiological and neuropsychological performances would also show a rise.

Inclusion Criteria:

• Alzheimer's disease patients diagnosed by a consultation memory (DSM- IV)
• Person with at least 60 years
• Person with a score higher than 15 in the Mini Mental State Examination
• No one can achieve the pedaling motion
• People who do not perform regular physical activity on bike
• Nobody has given free and informed consent in writing or obtained from a trusted person or the family environment
• People affiliated to a social security

Exclusion Criteria:

• Patient who refused to provide written consent
• Inability to pedal
• Recent myocardial necrosis (less than 3 months)
• Aortic Stenosis
• Uncompensated heart failure
• Unstable angina
• Ventricular arrythmia
• Pulmonary embolism
• Coxarthrosis, knee, ankle osteoarthritis
• Not affiliated to a social security
• Patient already participating in another biomedical research