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 older, the blood-brain barrier becomes more fragile. This tightly packed network of blood vessels normally shields the brain from harmful substances circulating in the bloodstream.
Over time, however, it can become leaky, allowing damaging compounds to enter brain tissue. The result is inflammation, which is linked to cognitive decline and is commonly seen in disorders such as Alzheimer’s disease.
Several years ago, the research team discovered that exercising mice produced higher levels of an enzyme called GPLD1 in their livers. GPLD1 appeared to rejuvenate the brain, but there was a mystery.
The enzyme itself cannot cross into the brain, leaving scientists unsure how it delivers its cognitive benefits.