Putting in long hours at the office is not as bright as you may think.

Chicago - We know all about the upsides of fresh air and a bit of scenery – but according to a study, going for a walk could also make your brain grow.

Researchers found that an energetic stroll three times a week increased the size of the hippocampus, the brain’s memory hub, which is one of the first areas to be destroyed by Alzheimer’s disease.

They asked 120 men and women aged between 55 and 80 to go for a brisk 40-minute walk three times a week.

Normally, the brain shrinks with age. But scans done after a year showed participants’ key regions – including the hippocampus – had grown by up to two percent, the American Association for the Advancement of Science’s annual conference heard.

Scientists explained that the growth took up to two years off the brain’s age – a change they said marked an “enormous” improvement.

However another group who had been asked to do a series of simple stretching exercises over the year saw the same brain regions shrink by around 1.5 percent.

Lead researcher Dr Kirk Erickson, from the University of Pittsburgh, said: “You don’t need highly vigorous physical activity to see these effects. This may sound like it is a modest amount but it’s like reversing the age clock by a couple of years.”

Dr Erickson explained that while exercise isn’t a magic bullet when it comes to fighting dementia, it seems to be one of the best ways of keeping the mind sharp.

He told the Chicago conference: “Most of the population is still very sedentary and it’s very difficult to get people up and moving.

“We aren’t training older people to run marathons. We are getting them up and moving at a moderate exercise level several times a week and seeing enormous improvements over a period of several months.”

He added: “The brain remains modifiable well into late adulthood. Even though brain shrinkage and cognitive decline occurs, it doesn’t seem to be as inevitable as we once thought.

“Physical activity seems to be one of the most positive approaches for affecting cognitive brain health and cognition in late adulthood and throughout lifespan.”

He went on to say that combining physical activity with mental exercise – such as solving puzzles – is also beneficial.

And Elizabeth Stine-Morrow, professor of psychology from the University of Illinois, stressed that it is never too early to start doing mental or physical exercise.

She said: “The earlier you change your everyday habits, the better off you are. But by the same token, it’s never too late.” - Daily Mail