Exercise Is the Most Powerful Brain Medicine

Alzheimer’s and dementia now affect over 55 million people worldwide—and the number is climbing fast. But one of the strongest defenses against cognitive decline isn’t a drug. It’s movement.

Recent meta-analyses and systematic reviews (2020–2024) consistently show that physical inactivity is among the top modifiable risk factors for dementia, rivaling genetic risk. Aerobic exercise in midlife is especially protective, with low fitness linked to nearly double the risk of cognitive decline later on.

Why? Exercise increases BDNF (brain-derived neurotrophic factor), improves cerebral blood flow, and even physically enlarges the hippocampus, a key memory center. A well-cited review found that regular moderate-to-vigorous exercise improves memory, executive function, and slows neurodegeneration in older adults—both healthy individuals and those with mild cognitive impairment.

The dose is surprisingly achievable: ~150 minutes of moderate activity or ~75 minutes of vigorous activity per week, plus strength training. Walking, cycling, swimming, resistance training, and mind–body practices like Tai Chi all show benefits—especially when movement challenges the brain.

If exercise were a pill, it would be the most powerful brain drug ever created. The science is clear. We just need to take it seriously.