According to a new study persistent stress can cause real damage to the brain. It can cause loss of memory as well as shrinkage of the brain matter say researchers. The results of this new study have been published in the latest issue of the journal Neurology this week.
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Study author Dr. Sudha Seshadri, professor of neurology at UT Health San Antonio explaines that higher levels of stress translates into raised levels of stress hormone cortisol in blood. A raised level of cortisol in blood can predict brain size, function and also performance of the individual when faced with cognitive tests. She said, “We found memory loss and brain shrinkage in relatively young people long before any symptoms could be seen.” It's never too early to be mindful of reducing stress,” she added. The lead author, Dr. Justin B. Echouffo-Tcheugui, an assistant professor of medicine at Johns Hopkins also said that symptoms of stress related memory loss and brain damage may not be evident until much damage has already been done.
Experts have said that stress hormone cortisol rises in blood when a person is faced with constant threats that instruct the body to be at the ready for “fight or flight”. This hormone then shuts down several bodily functions and concentrates on the “posed danger”. After the crisis is over the cortisol levels should drop and the functions of the body should resume. In individuals where this does not happen, the cortisol levels stay high and trigger the body for threats. This leads to problems with various functions, anxiety, heart disease, depression, weight gain or loss, difficulty sleeping, headaches, difficulty concentrating and memeory impairment. They add that the brain is most affected because it is vital that the brain receives nutrients to function normally.
There have been earlier studies that looked at the association between cortisol levels and memory loss among the elderly. This is the first study to look at younger individuals. This study has participants who average age is 48 years says Sheshadri. While earlier studies focussed on one area of the brain – the hippocampus – seat of memory, to detect association of memory loss and cortisol, this study looked at MRI scans of the whole brains, explained Sheshadri.
For this study the team of researchers looked at 2231 individuals who had no symptoms of dementia. They were given several cognitive tests and psychological exams to detect their thinking and memory skills. The participants were part of the long term Framingham Heart Study sponsored by the National Heart, Lung and Blood Institute (that has followed up individuals and their future generations in Framingham, Massachusetts, since 1948). The individual records were again measured after an 8 years gap. Blood cortisol levels were measured before breakfast (when the levels are highest during the day) followed by a brain MRI scan. Memory and cognitive tests were again administered to the participants. Factors that could affect the results such as age, gender, body mass index, blood pressure, smoking status, educational status, socioeconomic backgrounds etc. were accounted for. Results showed that those who had highest cortisol levels had the most memory loss as seen on the tests.
The study further noted that those with a raised level of cortisol also had more damage to parts of the brain that carry information across to different parts of the brain – the corona radiata and the part between two brain hemispheres – the corpus callosum. Those with higher cortisol levels also had a smaller cerebrum and thus their brain capacity was also reduced. Total cerebrum brain volume was 88.7 and 88.5 in people with normal levels and high levels of cortisol respectively. Experts have said that these changes are seen among middle aged individuals. With age there is likely to be more brain shrinkage and more memory loss. Women seemed to be worse affected with stress hormone cortisol than men, the study noted. Their brain size shrunk more with stress, write the researchers. Estrogen or the female hormone could play a role here say experts.
According to Sheshadri, this is an association study and not a “cause-effect” study. However the association is clear and people need to make lifestyle changes to reduce stress she said. Echouffo-Tcheugui also said that the next step would be a prospective study to see how stress alters the brain function. He added that it may be too early to “consider intervention” to remove stress related damage. Prevention and reduction of stress would be a wiser option. Suggested methods to reduce stress include getting enough sleep, exercising and meditating regularly.