Relax: A new study shows that people with higher levels of stress hormones tend to have smaller brains – but…
Relax: A new study shows that people with higher levels of stress hormones tend to have smaller brains – but that does not mean causing one another.
The study, published today in the journal Neurology reports less brain volumes and worse memories in people with higher than average levels of cortisol – popularly called stress hormone. But all media coverage that warns stress will decrease, your brain is premature. “Right now, all we can say is that A is associated with B, we can not really say anything about causal relationship,” said Sudha Seshadri, professor of neurology at the University of Texas Health Science Center in San Antonio and senior writer of the study.
“The results are fascinating,” said Bruce McEwen, neuroscientist at The Rockefeller University in New York, who was not involved in research. However, he adds, “Cortisol is the top of the iceberg. There is a lot going on.”
Cortisol is a hormone that the body pumps out in response to a number of stressors ̵
1; like sudden, psychological stress or chronic inflammation. And this is not the first time researchers have linked things to brain changes: Other studies have linked excessively high levels of cortisol to shrunk brain regions, as those parts of the brain involved in memory. Shrinking brains can signal neurological or cognitive impairment. While it does not necessarily mean brain cells die, it may mean that the precious cells lose their support systems, “McEwen said. “It’s a sign that things are not good.”
In today’s study, a research group led by Seshadri and Justin Echouffo-Tcheugui, a deputy professor at Johns Hopkins University, in the entire brain, appeared in more than 2,000 obviously healthy people. To find them, the research group turned to Framingham Heart Study, a massive three-generation study that has been monitoring a society in Massachusetts since 1948. The researchers took blood samples from study participants to measure cortisol levels and tested their memory, reasoning and attention. The researchers also portrayed the studyers’ brains to look for differences in brain volumes and changes in the white substance that isolates the brain’s biological wires.
Participants fell into three different groups with cortisol levels at low, medium and high ends of normal. And the researchers found that those with the highest cortisol levels tended to have worse memories and attention and less brain volumes – especially women. The high cardisol group also showed signs of harm to their white substance, which the study authors wondered can contribute to the differences in memory and attention: if you weaken the isolation, the signals will not travel along the lines so efficiently.
But McEwen warns readers against jumping to the conclusion that because cortisol is involved, stress is blamed. It’s true, surprisingly, stressful events can have your glands to spray out cortisol. But other insults can do the same: the body uses cortisol to tampon inflammation, for example. So chronic inflammation can also cause cortisol to rise. “It’s a police if you just dump this on word stress,” said McEwen. (“When you read the paper, did you see something about stress?”), Asks the study author Echouffo-Tcheugui. The answer is no – not to the reference section.)
It is possible that it is the cortisol that triggers the changes in brain volume. We have seen that earlier, says McEwen. But it is also possible that inflammation – if there is inflammation – can play a part in the white damage, researchers discovered. “Yes, it’s possible, there may be a number of factors like that,” Seshadri agrees.
McEwen hopes the team continues to dig into why some people had higher cortisol levels than others, and what might otherwise affect their brains, and the researchers suggested they should do it. “It’s a good step in the right direction,” said McEwen. “Underneath there is a lot of biology there that needs further investigation.”