5,000 steps a day can slow down Alzheimer's disease

Movement rejuvenates the brain – a new Harvard study (November 2025) shows that as few as 3,000 steps a day have measurable positive effects on cognitive health. This means: Even simple movement in everyday life can significantly slow mental decline in Alzheimer's, the most common form of dementia, without intense sports programs or marathon training.

About 1.8 million people in Germany live with dementia – most of them with Alzheimer's. Researchers have now found that even moderate physical activity – measured in daily steps – can slow the build-up of pathological tau deposits in the brain. These are considered one of the main drivers of cognitive decline in Alzheimer's.

In the long-term study, 296 older adults aged between 50 and 90 participated. All participants had no cognitive impairments, but some showed early signs of Alzheimer's in PET imaging (positron emission tomography) – so-called amyloid-β deposits, which often precede tau pathology. The researchers followed the subjects over several years.

• Daily activity was objectively measured with pedometers

• Annual PET scans were conducted to identify Alzheimer's markers such as amyloid-β and tau proteins in the brain.

• Annually, cognitive performance was assessed through standardized tests.

Cognitive health: Just 3,000 steps help – 5,000 to 7,500 are optimal.

Among physically active people with preclinical – thus still asymptomatic – Alzheimer's, a lower cognitive decline was recorded compared to physically inactive people. The evaluation showed:

• Those who walked 3,000 to 5,000 steps per day showed an average slowing of cognitive decline by about three years.

• Those who managed 5000 to 7500 steps daily even delayed the decline by up to seven years.

• Particularly striking: Exercise was not primarily associated with fewer amyloid plaques, but with slower tau build-up – precisely the process that destroys nerve cells.

Thus, walking is considered one of the few modifiable lifestyle factors for Alzheimer's prevention.

Why exercise helps with Alzheimer's

Exercise promotes brain circulation, reduces inflammation, and supports nerve cell regeneration. The Harvard study suggests that these processes start even with light activity. 3000 steps a day roughly correspond to a half-hour walk – an easy routine with a big impact. The Harvard study also suggests: The more steps, the greater the impact on cognitive health.

What are tau deposits – and why are they dangerous?

Tau is a protein that stabilizes the internal structures in healthy nerve cells and ensures the transport of nutrients. In Alzheimer's, it is chemically altered (hyperphosphorylated) – causing it to lose its function, clump together and form so-called neurofibrillary tangles inside the cell.

These deposits:

• disrupt the transport of vital substances in the cell

• block signal transmission

• and ultimately lead to the death of nerve cells

The stronger the deposits, the more severe the memory loss. The Harvard study shows for the first time in humans: More daily steps = slower tau increase.

What steps are the healthiest?

The Harvard study itself examined the total number of steps, not pace or terrain. However, complementary research suggests that the following types of walking are particularly healthy for the brain:

1. Brisk walking

• 100–120 steps / minute

• increases blood flow and oxygen supply to the brain

• increases the formation of neural growth factors (BDNF), which promote the formation of new synapses

2. Walking in nature or on uneven terrain

• trains balance and coordination

• reduces stress hormones that can promote Alzheimer's

3. Mindful or social walking

• activates emotional brain regions

• reduces cortisol and promotes well-being

4. Regular walking

• daily 30 minutes, preferably in stages

• is more effective than rare intense sports sessions

Limits of the Harvard study on Alzheimer’s

The researchers emphasize: It is an observational study – it does not prove causation. More active people often also have other healthy lifestyle habits (nutrition, sleep, social activity). Nevertheless, the study is unique because it is the first to show with Tau-PET scans that exercise can directly affect Alzheimer's biology.