LONDON: Moderate but regular exercise can boost the size of parts of the brain that shrink with age, according to scientists who believe light physical activity is one of |the best ways of preventing senile dementia.
A study involving 120 people aged between 60 and 80 found that walking briskly for 30 to 40 minutes a day, three times a week, was all it takes to "re-grow" the structures of the brain linked with cognitive decline in later life.
The effect was equivalent to stopping the ageing clock by between one and two years, |and is one of the first scientifically controlled studies showing the power of physical |exercise in delaying mental decline, scientists said.
Brain scans taken before and after the year-long study showed that two regions of the brain in particular - the prefrontal cortex and the hippocampus - grew in volume among the group undertaking light aerobic exercise, while they continued to shrink in those who were given only stretching tasks. The exercise group also did better at cognitive tasks which tested things such as memory, language ability and attention, which are known to decline with age.
"The results suggest that brain and cognitive function of the older adults remain plastic and highly malleable. There is not this inevitable decline |that we used to think there was. We can improve brain function by relatively modest amounts of physical activity," said Kirk Erickson of the University of Pittsburgh.
"Between six months and one year of regular physical activity can actually increase the size of the prefrontal cortex regions and another region of the brain called the hippocampus," he told the American Association for the Advancement of Science in Chicago.
"Both of these regions deteriorate and shrink as we get older. The prefrontal cortex is really involved in a lot of higher-level cognitive functions and the hippocampus |is well known to be involved |in memory formation, and when it shrinks it leads to Alzheimer's and dementia.
While there was a 2 percent average increase in volume within the exercise group, the same brain regions shrank by about 1.5 percent in the other group, which is the normal rate, Erickson said.
"You don't need highly vigorous physical activity to see these effects… it only needs to be moderate and not even for that long. They say they feel as if the fog has lifted. We get those types of comments quite a bit, so anecdotally it seems to benefit these cognitive functions.
"All the evidence is lining up that this is a very effective non-pharmaceutical approach to treating dementia… If we measured these people for a longer period of time we'd probably find that we are slowing the decline rather than completely mitigating it.
"But it might slow it down for a long period of time. We cannot say it's the magic bullet cure for Alzheimer's - there isn't one."