Ocusfocus |

Stress might lead to memory loss and brain shrinkage, study says


October 24, 2018 - 6:48 pm

By Sandee LaMotte, CNN


"Higher levels of cortisol, a stress hormone, seem to predict brain function, brain size and performance on cognitive tests," said study author Dr. Sudha Seshadri, professor of neurology at UT Health San Antonio.

"We found memory loss and brain shrinkage in relatively young people long before any symptoms could be seen," Seshadri said. "It's never too early to be mindful of reducing stress."

Too much 'flight or fight'

Cortisol is one of the body's key stress hormones, best known for its role in our "flight or fight" instincts. When we are stressed and on high alert, the adrenal glands produce more cortisol. The hormone then goes to work shutting down various bodily functions that might get in the way of survival.


READ: US approves first new type of flu drug in 2 decades


"The brain is a very hungry organ," said Keith Foley, who directs scientific programs and outreach for the Alzheimer's Association. "It requires an outsized amount of nutrients and oxygen to keep it healthy and functioning properly. So, when the body needs those resources to deal with stress, there's less to go around to the brain."

High stress connected to memory loss




All were part of the Framingham Heart Study, a long-term study sponsored by the National Heart, Lung and Blood Institute. It's been following the health of residents of Framingham, Massachusetts, and their offspring since 1948.

READ: Broken heart syndrome: What is it?



"I wasn't surprised by the changes in cognition," said Foley, who was not involved in the study. "If you have higher cortisol you're probably stressed out and likely to have more difficulty on cognitive tasks."

Stress affects brain structure, too

What was surprising, said Foley, was the study's findings of the effects of cortisol on brain structure.




"I was surprised you would be able to see such a large change in brain structure with high cortisol levels compared to moderate levels of cortisol," said Foley. "If you're seeing structural brain changes in midlife, you can imagine what is happening by the time you get old enough to develop dementia."

READ: A Mediterranean diet can lower the risk of stroke, study finds


"Estrogen can increase cortisol," said Dr. Richard Isaacson, who directs the Alzheimer's Prevention Clinic at Weill Cornell Medicine, "and about 40% of the women in the study's high cortisol group were on hormone replacement." Isaacson was not involved in the study.


"That does not completely rule out an adverse impact of estrogen replacement," Seshadri said, "but makes it less likely to the main story."


Foley agrees. "We know, for example, that people who exercise throughout life have a lower risk of developing dementia," he said. "Take some time for yourself. Do some meditation. There are ways to control stress that will lead to a beneficial outcome."
