Daily brisk walk or bike ride can reduce risk of Alzheimer’s

By Mark Waghorn via SWNS

A daily brisk walk or bike ride can reduce older people's risk of Alzheimer's, according to new research.

Regular exercise boosts connections between brain cells - protecting them against age related decline.

The junctions, or synapses, pass messages using chemicals called neurotransmitters.

When the elderly stay active their grey matter has more of the transmitters, the study found.

The phenomenon was identified even in those whose brains at autopsy were riddled with toxic proteins linked to dementia and other neurodegenerative diseases.

"Our work is the first that uses human data to show synaptic protein regulation is related to physical activity and may drive the beneficial cognitive outcomes we see,"said lead author Dr. Kaitlin Casaletto, of the University of California, San Francisco.

The effects on cognition have been shown in mice but are much harder to demonstrate in people.

Dr. Casaletto and senior author Professor William Honer analyzed data on physical activity of participants who agreed to donate their brains when they died.

The volunteers from the Rush Memory and Aging project in Chicago wore monitors 24 hours a day for up to ten days before annual cognitive exams.

"Maintaining the integrity of these connections between neurons may be vital to fending off dementia, since the synapse is really the site where cognition happens,"Casaletto said.

"Physical activity - a readily available tool may help boost this synaptic functioning."

Those who remained active had higher levels of proteins that facilitate the exchange of information between neurons.

It shed light on an earlier finding by Honer that people who had more when they died were better able to maintain brainpower late in life.

To his surprise the effect ranged beyond the hippocampus, the brain's memory center.

It encompassed other brain regions associated with cognitive function, he explained.

"It may be physical activity exerts a global sustaining effect, supporting and stimulating healthy function of proteins that facilitate synaptic transmission throughout the brain,"said Honer, of the University of British Columbia, Canada.

The brains of most older adults accumulate amyloid and tau. The rogue proteins gather in clumps and tangles, respectively, and are the hallmarks of Alzheimer's.

Many scientists believe amyloid collect first, then tau, causing synapses and neurons to fall apart.

Casaletto previously found synaptic integrity, measured in the spinal fluid of living adults and brain tissue after post mortem, dampened the relationship between amyloid and tau, lessening 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," she said.

"Taken together, these two studies show the potential importance of maintaining synaptic health to support the brain against Alzheimer’s disease."

For healthy adults, doctors recommend at least 150 or 75 minutes of moderate or vigorous aerobic activity, respectively, a week.

Alzheimer's and other forms of dementia affect more than 920,000 people in the UK, a figure that will rise to two million by 2050.

With no cure in sight, there is an increasing focus on potentially preventative lifestyle factors, including getting plenty of exercise and eating healthily.

The study is in Alzheimer’s & Dementia: The Journal of the Alzheimer's Association.