When it comes to keeping your brain healthy — and working at its best — doctors have long advised patients to "use it or lose it." The idea is to keep the intellectual highways humming; if circuits aren't used, they tend to deteriorate and eventually wither away, leading to dementia, and in some cases,Alzheimer's. But new research provides a twist on this familiar advice — it turns out that some people benefit more from using it than others.
Psychiatrists led by Guy Potter at Duke University conducted a study of more than 1,000 male twins, most of whom were World War II veterans. Potter collected 50-year-old data on the vets' IQ scores when they joined the Army, and then compared them to cognitive test scores the men generated after they retired from various jobs. He found that those who scored in the bottom quartile of the IQ scale when they were in their 20s, and then took on mentally challenging jobs, had the greatest gains on the cognitive tests in their 70s. "Being in a more complex job later in life helped them to develop skills they might not have had, or pushed them in ways so they were able to overcome their intellectual limitations," says Potter.
That means that those with the lowest cognitive abilities are most likely to lose it if they don't use it, and also most likely to protect themselves from dementia and other cognitive problems by keeping their brain circuits active. Not surprisingly, the jobs that proved most beneficial to these folks include the higher degree professions such as law, medicine and journalism, but any career that required multi-tasking, organizing and managerial skill also boosted cognitive abilities later in life. "Any job that requires you to keep fresh, whether it is new sales techniques or learning about new products, can keep you stimulated intellectually," says Potter. Even being self-employed can qualify, since it requires considerable managerial and organizational skills. "People who are self-employed contractors or plumbers, for example, may be doing plumbing most of the day, but they have to also do inventory, prepare bids, and schedule workers, all of which adds a level of complexity."
While on the face of it, Potter's study reinforces previous studies' findings about the importance of keeping brain circuits active, it is the first to tie it to the subjects' baseline intellectual ability. In other studies, researchers could never be sure, for instance, that people who remained intellectually active and therefore suffered fewer cases of dementia, didn't have some sort of brain reserve, or start out with a higher level of cognitive ability that served as a buffer during their declining years.
Since Potter could use the IQ scores from early in life as a baseline, he showed that regardless of how much intellectual ability a person starts out with, a mentally demanding job can keep his brain healthy well into retirement. In fact, the gains for people who have high IQs are relatively small, leading Potter to speculate that having a complex job, "may make up for a lack of advantage early in life, whether they be socioeconomic or otherwise." he says. So depending on what you do for a living, that daily grind may actually be the ultimate brain booster.