If you think that mental fatigue, forgetfulness and even dementia and Alzheimer's disease are unavoidable with time, the science of ageing has news for you. By stressing your mind in productive ways, you can lower your risk of mental decline.
You don't need fancy computer programs or complicated ‘brain games’ to do it, simple ‘brain calisthenics’ (one neuroscientist calls them neurobics—aerobics for your brain cells) that involve new ways of doing everyday things are all it takes.
During autopsies of 137 nursing home residents, ten people were found to have the classic brain changes of Alzheimer's disease despite having had few signs of the disease while alive.
Indeed, their mental performance had been as good as that of residents whose brains showed no such changes after death. When the scientists looked further, they found a possible explanation: the patients’ brains weighed more and had more neurons than residents of the same age without Alzheimer's brain changes.
One possible reason: these people had greater ‘cognitive reserve’—a savings account of extra pathways that allowed them to offset the changes and function more normally for far longer.
Studies since have suggested that up to 20 per cent of people who had no signs of Alzheimer's in their daily lives still have brain changes characteristic of the disease at post-mortem.
Even more exciting: neuroscientists have since found that people who use their brains more often seem to possess these brain-saving reserves. And they believe that stressing the brain in ways similar to how we stress muscles during exercise can produce similar benefits—a stronger, fitter, more flexible brain.
In one study of 1,772 older people with normal brain function, the odds of developing dementia dropped 12 per cent for each leisure-time activity they took up. Those with the most activities were 38 per cent less likely to develop thinking problems during the seven-year study.
Exercise, spending time with friends and intellectual pursuits all helped, but activities that required the most concentrated brain power, such as reading, doing crossword puzzles and playing games that call for strategising, were the most protective.
While ‘bad stress’ leads to depression and cognitive problems (and even physical ailments), this ‘good stress’ seems to help the brain by stimulating nerve cells, increasing blood flow, and boosting production of neurotrophins, the chemicals that protect brain cells.
Adding ‘neurobics’ to your mix of brain-healthy pursuits could make an even bigger difference, says Lawrence Katz, PhD, a brain researcher at Duke University Medical Center in North Carolina.
"Your brain is activated by your senses and you encounter new stimuli all the time," Dr Katz notes. "Activities that involve one or more of your senses in a new way… can strengthen synapses between nerve cells and make brain cells produce more brain-growth molecules."
Continued learning and mental stimulation "literally grows your brain," says Professor Ian Robertson, dean of research at Trinity College Institute of Neuroscience in Dublin.
More active brains develop a richer and more densely connected network of brain cells, and this brain strengthening may be one reason why dementia is less common among people who have spent more time learning. Reduced mental sharpness is not inevitable in old age, he stresses, any decline can usually be stopped or even reversed by mental exercise.
And you don't need to stretch your brain for long to benefit. In a study of nearly 3,000 people aged 65 to 94, just 10 hours’ training over several weeks in memory, problem-solving and decision-making resulted in significant and prolonged increases in cognitive ability.