Exercise alters brain chemistry to protect ageing synapses

Kirikiriroa - When elderly people stay active, their brains have more of a class of proteins that enhances the connections between neurons to maintain healthy cognition, a University of California San Francisco study has found.

This protective impact was found even in people whose brains at autopsy were riddled with toxic proteins associated with Alzheimer's and other neurodegenerative diseases. The research showed enhanced nerve transmission was seen in older adults who remain active.

The university work is the first that uses human data to show that synaptic protein regulation is related to physical activity and may drive the beneficial cognitive outcomes.

The beneficial effects of physical activity on cognition have been shown in mice but have been much harder to demonstrate in people.

Researchers tracked the late-life physical activity of elderly participants, who also agreed to donate their brains when they died.

Maintaining the integrity of these connections between neurons may be vital to fending off dementia. Physical activity may help boost synaptic functioning.

The study showed that elderly people who remained active had higher levels of proteins that facilitate the exchange of information between neurons.  

The researchers found that the effects ranged beyond the hippocampus, the brain's seat of memory, to encompass other brain regions associated with cognitive function.

It may be that physical activity exerts a global sustaining effect, supporting and stimulating healthy function of proteins that facilitate synaptic transmission throughout the brain.

The brains of most older adults accumulate amyloid and tau, toxic proteins that are the hallmarks of Alzheimer's disease. Many scientists believe amyloid accumulates first, then tau, causing synapses and neurons to fall apart.

The researchers previously found that synaptic integrity, whether measured in the spinal fluid of living adults or the brain tissue of autopsied adults, appeared to dampen the relationship between amyloid and tau, and between tau and neurodegeneration.

In older adults with higher levels of the proteins associated with synaptic integrity, this cascade of neurotoxicity that leads to Alzheimer's disease appears to be attenuated. The study show the potential importance of maintaining synaptic health to support the brain against Alzheimer's disease.