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We often talk about the negative side of stress and indeed, in high doses, it is harmful to health. But in small doses, stress would on the contrary be beneficial for the brain and working memory, according to a study published by scientists from the University of Georgia in the United States.
Cardiovascular risk factor, aging accelerator, generator of migraines… Stress is often criticized for its very real negative sides, which occur when it is too high. But low to moderate stress causes our brains to work better, according to the results of a study.
Analysis of MRI and working memory data
The researchers analyzed MRI data from the Human Connectome project. This represents brain information from brain imaging scans performed on more than 1,000 people of various ethnic backgrounds.
To assess perceived stress levels, participants answered questions about how often they experienced certain thoughts or feelings. For instance, “In the past month, how often have you been upset because of something that happened unexpectedly?” and “In the past month, how often have you found that you couldn’t cope with all the things you needed to do ?”
Analysis of their social networks
In parallel, to analyze their working memory, participants were given a series of four types of images – such as tools and people’s faces – and were then asked to recall a moment later if they was the same photos shown before.
Finally, the researchers also examined participants’ social networks using a variety of measures, including how individuals felt about their own ability to handle unexpected events, how satisfied they were with the importance and meaning of their life and the availability of friend-based support on these networks.
“Low to moderate” stress levels are beneficial
The results suggest that people who reported low to moderate levels of stress had increased activity in parts of the brain that involve working memory. On the contrary, participants who reported experiencing high chronic stress levels showed a decline in these areas.
For the authors, low to moderate levels of stress improve working memory and make it easier to complete simple tasks, like remembering a phone number or remembering directions. The researchers would like to point out that “The results are specific to low to moderate stress. Once your stress level rises above moderate levels and becomes constant, that stress becomes toxic.”
The support of friends, a major support
The researchers then analyzed MRIs of the participants’ brains as they performed the tasks to assess neural activation in different parts of the brain.
Not surprisingly, participants who reported having more support from family and friends seemed more able to cope with low to moderate levels of stress in a confident manner.
“You must have the right resources to be stronger in the face of adversity and stress” write the authors. “For some people, being exposed to adversity is a good thing. But for others, maybe not. But you may be able to handle more stress if you have a supportive community or family.” say the scientists.
The opinion of Dr Joachim Müllner, psychiatrist and member of the Doctissimo expert committee
“This study shows that mild to moderate stress increases and improves “resilience” abilities, ie the ability to adapt to difficulties. This improvement is done through the stimulation and then the improvement of certain cognitive performances. Such as, for example, cognitive flexibility, i.e. the ability to switch from one task to another, memory for image sequences, which consists of remembering a series of increasingly longer, working memory and processing speed.
It is indeed quite logical that stress, up to a certain point, improves performance since this is the very purpose of this physiological and emotional reaction: to increase the capacity of our organism to react to problematic situations by increasing our physical reactivity, for example muscular, as well as our intellectual capacities and for example our speed to process the information present.
The authors also make a very fair comparison: light to moderate stress acts like manual labor on the palms of the hands by making wedges, while too much stress acts like too much manual labor by injuring the skin.