Harmful Effects of Stress on Your Brain
You are probably aware of the negative consequences of stress in your life. Maybe you suffer from stress-induced headaches, worry about stress contributing to heart disease, or experience the effects of stress in increased anxiety or depression. Any which way it manifests, stress can have a terrible impact on your health. And now, there is yet another reason to get your stress levels under control. New research suggests, perhaps not surprisingly, that unchecked stress can be harmful to your brain.
The study, which took place at the University of Texas Health Science Center at San Antonio, found that high levels of stress may raise the risk of memory loss and brain shrinkage as early as middle age.1 These results are based on an investigation that included more than 2,000 men and women who had not exhibited any symptoms of dementia at the start of the study. All the subjects were part of the larger Framingham Heart Study, a long-term, health-related research project involving Massachusetts residents.
The participants underwent a round of testing, taking several psychological examinations that evaluated their cognitive abilities. Approximately eight years later—when the volunteers were at an average age of just 48—follow-up assessments were conducted. During these sessions, blood samples were drawn prior to breakfast to obtain fasting blood serum cortisol levels. In addition, brain scans were performed using MRIs, and the same battery of psychological tests given years earlier was repeated.
Unfortunately, the news was bad for those with greater amounts of cortisol—the stress hormone produced by our adrenal glands—both in terms of memory decline and actual structural changes to the brain. But surprisingly, the effects only appeared to affect women’s brains significantly—not so much men. Those women with the highest cortisol levels in their blood showed signs of the most memory loss during testing.
And the MRIs indicated that the brains of the subjects with more cortisol in their bloodstreams were structurally different than their peers with lower cortisol levels. Damage was noted to areas that transfer information around the brain and between the brain’s two hemispheres; and the cerebrum, which is involved in processes such as coordination and emotions, was measurably smaller. Cerebral brain volume dropped in those with high cortisol levels to an average of 88.5 percent of total brain volume, in contrast to the 88.7 percent average in those with lower cortisol levels. At first glance, this might not seem like a large difference (0.2%), but in terms of brain volume, it actually is. As Keith Fargo, who directs scientific programs and outreach for the Alzheimer's Association, said, “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."
All the findings held up even after the researchers controlled for factors including age, gender, body mass index, and whether the participant was a smoker. It should be noted that approximately 40 percent of the female volunteers were using hormone replacement, and estrogen can raise cortisol levels. Since the effects were seen predominantly in women, the investigators also made adjustments to the data to consider the impact of hormone replacement therapy, but again, the results held firm. So, while it’s possible that the hormone replacement was contributing to the excessive cortisol, that would represent only a part of the picture.
The study was not designed to prove cause and effect, but it certainly provided evidence of a strong association between high cortisol levels and both decreases in cognitive function and brain shrinkage. And keep in mind that these findings are particularly scary since the changes became evident while the subjects had an average age of just 48. That is long before most people begin exhibiting symptoms of dementia, which begs the question of what their brains will look like in another 10 or 20 years.
That said, the important takeaway here is not so much to worry about any damage you might have already done, but to focus on making improvements moving forward. It is impossible to eliminate stress, but it’s essential to learn to manage it better. Daily exercise is a great stress reliever that also helps prevent cognitive decline. Other good options include mindfulness techniques, yoga, and taking a warm bath listening to your favorite music. Try a few strategies and stick with whatever works for you so you can keep your stress levels down and your brain healthy.
- 1. Echouffo-Tcheugui JB, Conner SC, Himali JJ, et al. "Circulating cortisol and cognitive and structural brain measures: The Framingham Heart Study." Neurology. 2018 Oct 24. pii: 10.1212/WNL.0000000000006549. https://www.ncbi.nlm.nih.gov/pubmed/30355700.