Washington DC, Feb. 21 -- Exercise may sharpen the mind by repairing the brain's protective shield. Researchers found that physical activity prompts the liver to release an enzyme that removes a harmful protein, causing the blood-brain barrier to become leaky with age.

In older mice, dialling down this protein reduced inflammation and improved memory. The discovery points to a surprising body-to-brain pathway that could inspire new Alzheimer's therapies.

Researchers at UC San Francisco have identified a biological process that may explain why exercise sharpens thinking and memory. Their findings suggest that physical activity strengthens the brain's built-in defence system, helping protect it from age-related damage.

As people grow old...