Stress Can be Good for You: Brain Performance Improved by Short-lived Events

Stress can make your hair fall out. Stress can make sleep poorly. Stress is, presumably, always bad--or is it? New research reveals that some stress can be good for you.

In order to see exactly how stress affects someone, researchers looked at rats. They subjected the animals to acute but short-lived stress, confining them in their cages for a few hours. This caused the stress hormone, corticosterone, to rise to levels as high as that of chronic stress--though only for a few hours.

Chronic stress actually elevates levels of glucocorticoid stress hormones, which suppress the production of new neurons in the hippocampus. This, in turn, impairs memory. Chronic stress doesn't only impact the brain, though; it can also increase the risk of obesity, heart disease and depression.

Yet after subjecting the rats to short-lived stress, the researchers found that they performed better on a memory test two weeks after the stressful event. It turned out that the stress doubled the proliferation of new brain cells in the hippocampus, specifically in the dorsal dentate gyrus. By using cell labeling techniques, the researchers were able to confirm that the new nerve cells triggered by the stress were the same ones involved in learning new tasks two weeks later.

"I think intermittent stressful events are probably what keep the brain more alert, and you perform better when you're alert," said Elizabeth Kirby, the lead researcher, in a press release.

The proliferation of nerve cells after a stressful event was triggered by the release of a protein, fibroblast growth factor 2 (FGF2), by astrocytes, which are brain cells formerly thought of as support cells. With this latest research, though, scientists have now shown that astrocytes play a far more critical role in regulating neurons than previously thought.

"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," said Daniela Kaufer, associate professor of integrative biology at the University of California, Berkley, in a press release. "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."

The paper was published in the journal eLife.