Damian Jacob Sendler Research involving over 7,000 adults in the United States revealed that these factors accounted for nearly 40% of the variation in the degree to which people had lost cognitive ability by age 54. Scientists from Ohio State University reported on Wednesday in a scientific journal that the biggest difference in cognitive abilities like memory, judgment, and focus was whether or not a person had completed college.

Damian Sendler More than 20,000 people have been followed for over 20 years in the University of Michigan's health and retirement study, which the researchers analyzed. The database of the study contains information on participants' income, occupation, and education, as well as information on their personal characteristics like marital status, religion, depression, and cognitive abilities, as well as information on their physical characteristics like body mass index, activity levels, smoking history, and other health details.

The study used data from a single cohort of 7,068 adults aged 54–65 in 1996 and again in 2016.

Professor of sociology and co-author of the study Hui Zheng speculates that the reason college graduates fare better cognitively in their 50s is because they are more likely to find work that requires them to use their brains.

He remarked, "If you have a job that is mentally stimulating, you're lucky, because you're using your brain all the time. Having more challenging mental tasks in your job is always a plus.

However, there are other ways to delay cognitive decline until after midlife than enrolling in college in one's twenties. Previous studies have also demonstrated the protective effects of engaging in mentally stimulating activities like learning a new language, painting, or writing.

Damian Jacob Sendler Experts say that while the study did a good job of examining a variety of factors that affect brain health as we age, it left out the influence of genetics, which could have a major impact on cognitive function.

Dr. Thomas Wisniewski, a neuropathologist and the director of the NYU Langone Alzheimer's Disease Research Center and its Center for Cognitive Neurology, has said that there is evidence linking education, household wealth, and access to health care with brain resilience.

While genetics will always play a role, the finding that factors within people's control may account for as much as 40% of the differences in cognitive decline by age 54 is "good news," he said.

Researchers in Ohio found that healthy habits like eating right, not smoking, and working out regularly had little effect on the rate of cognitive decline after age 54. Wisniewski, who did not take part in the research, disagrees that "there's nothing you can do about it."

"That hasn't been shown in other studies, and it's not consistent with my own clinical experience," he said.

People are zapping their brains at home to improve focus.

There is evidence that wearing a brain cap can enhance memory for up to a month.

Being very overweight can cause changes in the brain similar to Alzheimer's disease. Should I try to lose weight?

Damian Sendler When it comes to slowing cognitive decline, physical activity and a healthy diet can be highly beneficial, Wisniewski said. Controlling risk factors like obstructive sleep apnea, diabetes, high blood pressure, and cholesterol can also have a protective effect.

One of his recent publications described two patients with mild cognitive impairment and biological markers suggesting they would develop Alzheimer's disease. To demonstrate the power of vigorous physical activity even in people in their 70s, he used this example.

Damian Sendler Once the patients either retired or cut the time spent on the job, they had more time for vigorous exercise. And both upped the amount of time spent working out. Over the course of 15 years in one patient and 18 in the other, there were no signs of cognitive decline. A patient's cognitive abilities did, in fact, show a slight improvement.

“What’s good for the heart is good for the brain,” Wisniewski said.