How to jog your memory into shape
Exercise, such as jogging, could improve mental and physical fitness.
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LONDON, England (CNN) -- Physical exercise could help keep the brain alert and fully functioning as the body ages, new research has suggested, while a newly developed training program has shown regular mental exertion is just as important.
A study, reported in Nature and first featured in the Journal of Neuroscience, found that exercise flush out a toxic molecule from the brain and allowed it to be replaced a beneficial molecule instead.
That molecule, the researchers said, helped to protect brain nerve cells.
"Our experiments support the idea that exercise is a good approach to all types of problems in the brain and that a sedentary lifestyle is a risk factor," said Ignacio Torres-Aleman, leader of the study at the Cajal Institute in Madrid.
It is believed the study could help explain why physically and mentally active people seem less likely to be affected by Alzheimer's disease or its symptoms.
Studying mice, the team found that exercise helped a protein called megalin eject molcules of a protein called amyloid-beta from the brain and into the bloodstream. Amyloid-beta has been found to accumulate in clusters in the brain of an Alzheimer's patient.
By contrast, megalin also binds in the blood to a protein called insulin-like growth factor and carries it back to the brain. This protein is the agent that help muscles build size after exercise, but also acts to keep nerve cells healthy in the brain.
As megalin levels decrease with age, some researchers believe this shows a molecular link between neurodegenerative disease and ageing, Nature said.
The Madrid researchers artificially raised the amount of megalin in mice with an Alzheimer's-like disease, then administered a maze test for the mice to complete.
The team found the mice with extra megalin performed better in the test.
But not everyone is convinced. Paul Adlard, University of California neuroscientist, had carried out a similar study on mice with a different model of the disease.
His results suggested exercise did not help boost levels of the beneficial protein, Nature reported.
Others suggested the research had, at the least, the potential to spark the development of drugs that could boost the megalin levels in the body.
Use it or lose it?
Meanwhile, a new training program developed by researchers at UC, San Francisco, claims to slow down mental deterioration by as much as 10 years.
As people age, "sensory information gets encoded less accurately, and the brain has to look and listen longer before it can make a decision about what it's seeing or hearing", said Michael Merzenich, a UCSF neuroscientist, quoted in Technology Review.
For example, older people are worse at remembering two musical tones played in quick succession. But slowing down the tones -- by only a few hundred milliseconds -- completely eliminated the imbalace.
Merzenich and colleagues developed a program that allows people to train themselves to keep processing new information at better levels.
In a test on 95 Californians aged from 63 to 94, the results of which were presented last month, those who trained an hour a day showed "significant improvement", with most taking 10 years off their neurocognitive "age."
Linda Ercoli, an expert at UCLA's Neuropsychiatric Institute, told Technology Review the results were "encouraging" but incomplete.
It was not known how long the effects of the training would last, not was it clear how much it would improve an older person's ability to improve performance on everyday functions not related to the program, such as driving or following conversations in a noisy room, the magazine reported.
The team plan to gauge general effects in the next test, it said.
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