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Being overworked and stressed may have a positive side, say scientists who found short-lived stress primes the brain for improved performance and optimal alertness.
Researchers from University of California, Berkeley uncovered exactly how acute stress - short-lived, not chronic - primes the brain for improved performance."You always think about stress as a really bad thing, but it's not. Some amounts of stress are good to push you just to the level of optimal alertness, behavioural and cognitive performance," said Daniela
Kaufer, associate professor of integrative biology at the UC Berkeley.
In studies on rats, they found that significant, but brief stressful events caused stem cells in their brains to proliferate into new nerve cells that, when mature two weeks later, improved the rats' mental performance."I think intermittent stressful events are probably what keeps the brain more alert, and you perform better when you are alert," she said.
Fellow researcher Elizabeth Kirby subjected rats to what, to them, is acute but short-lived stress - immobilisation in their cages for a few hours. This led to stress hormone (corticosterone) levels as high as those from chronic stress, though for only a few hours.
The stress doubled the proliferation of new brain cells in the hippocampus, specifically in the dorsal dentate gyrus.
Kirby discovered that the stressed rats performed better on a memory test two weeks after the stressful event, but not two days after the event.
Using special cell labelling techniques, the researchers established that the new nerve cells triggered by the acute stress were the same ones involved in learning new tasks two weeks later."In terms of survival, the nerve cell proliferation doesn't help you immediately after the stress, because it takes time for the cells to become mature, functioning neurons," Kaufer said."But in the natural environment, where acute stress happens on a regular basis, it will keep the animal more alert, more attuned to the environment and to what actually is a threat or not a threat," Kaufer said.
They also found that nerve cell proliferation after acute stress was triggered by the release of a protein, fibroblast growth factor 2 (FGF2), by astrocytes - brain cells formerly thought of as support cells, but that now appear to play a more critical role in regulating neurons.
The study was published in the journal eLife.
