Key to mental fitness - work the brain

Sir Brian Lochore. Photo / APN

Put down the Sudoku puzzle and never mind finishing the 5000-piece jigsaw - latest research reveals it's physical exercise, not brain gymnastics, that will keep your mind sharp into old age.

Professor Winston Byblow, a brain researcher and sport and exercise scientist at the University of Auckland, has found regular exercise significantly increases the flow of oxygen to the brain, nourishing cells and helping thought.

Walking for 45 minutes five times a week was enough to increase fresh oxygen by about 17 per cent, the equivalent of reducing your brain's age by 10 years. "If you needed another reason to exercise, this is it," Byblow said.

By adding strength training to the mix, the benefits were even greater, he added.

And his findings were backed up by All Blacks great Sir Brian Lochore who, at 70, is in perfect mental health and has never completed a crossword or Sudoku puzzle.

The grandfather-of-eight has stayed fit throughout his life. Since retiring from the field, Lochore has worked on his Masterton farm and "played the occasional game of golf".

"I find when you're fit you're capable of making better decisions. The less you do physically, the less you think," he said.

Byblow has studied research from New Zealand and around the world looking at the factors affecting cognitive decline and will present his findings at a public lecture next Saturday.

He said it was well documented that the brain shrank by about 5 per cent every decade after the age of 40, and even faster beyond 55 years. This impaired memory and mental abilities.

But Byblow said research showed people who picked up physical activity later in life not only slowed brain decline but stimulated its growth.

"It's one thing to say it's not shrinking as quickly but it's remarkable you can actually reverse the effects of ageing."

Byblow said there was no evidence that performing mental exercises had any effect on the brain's decline.

"If you do Sudokus you might get good at doing Sudokus but you may forget where you parked the car.

"Think of it as taking your hippocampus out for a walk." The hippocampus is the part of the brain responsible for long-term memory and learning. "Everything you know is in there," Byblow said.

Byblow's presentation coincides with Brain Day and is part of a series of public lectures, activities and workshops put on by the university's Centre for Brain Research.