Stress is not always a bad thing. We need challenges to keep us active and alert, mentally as well as physically. But science is beginning to discover what we all know instinctively— ongoing stress fries your brain.
Sharp Brains has an excellent article which explains how stress affects your brain:
Too much stress damages your brain
Cortisol, the most prominent of the glucocorticoids, does an excellent job of allowing us to adapt to most stressors which last more than a couple of minutes but under an hour. Short term it will actually enhance our immune system, memory and attention. Long term, past ½ hour to an hour, excessively elevated cortisol levels start to have detrimental effects. It seems we were designed more to deal with short spurts of high stress, such as beating back that attacking bear, rather than long drawn-out stressors such as meeting deadlines.
Our brains appear to be most vulnerable to the effects of excessive stress in a region called the hippocampus. The hippocampus is a mass of neurons each with multiple branch-like extensions (dendrites and axons) which make connections (synapses) with other neurons all across the brain. Among other things, this region is important in dealing with emotions and consolidating new memories. As with all brain regions, its ability to adapt relies upon being able to alter the branching and connections of its neurons. The hippocampus is also one of the only regions of the brain known to be able to produce new neurons, a process called neurogenesis.
Memory and learning are negatively affected
Enduring a high stressor for more than 30 minutes to an hour has been shown to negatively impact the hippocampus in various ways. To begin, sustained exposure to higher than normal levels of cortisol results in the pruning back of the number of branches and synaptic connections of hippocampal neurons. By a variety of mechanisms, these conditions also increase the rate of cell death in this region of the brain.
As if this wasn’t bad enough, recent research is also demonstrating that sustained increases in glucocorticoid levels also have negative effects, impairing the hippocampus’s ability to create new neurons.
Over a period of time, all of this results in the shrinking in size of the hippocampus with associated declines in cognitive function, including the ability to retain new information and adapt to novel situations.
These changes in the brain are also accompanied by anxiety and depression. Science is beginning to show how this happens - and what we might do about it.
Brain changes in anxiety and depression
Research has shown that mood disorders take a toll on patients' brains as well as on their lives. Postmortem studies and brain scans have revealed that the hippocampus (the brain's memory center) can shrink and atrophy in people with a history of depression and other mood disorders. People who live with mood disorders are also known to have low levels of brain-derived neurotrophic factor (BDNF), a growth factor that keeps neurons healthy. They also have low activity in the neuritin gene, which codes for a protein of the same name that may protect the brain's plasticity: its ability to reorganize and change in response to new experiences.
Ronald Duman, a neurobiologist at Yale University, and colleagues wondered if the poorly understood neuritin might play an important—and heretofore overlooked—role in depression and other mood disorders. They induced depression in a group of rats by subjecting them to chronic, unpredictable stress. Depriving them of food and play, isolating them, and switching around their day/night cycles for about 3 weeks left the rats with little interest in feeding or enjoying a sweetened drink. The rats also gave up and became immobile instead of swimming when placed in a tub of water—another measure of rodent depression.
All of the depressed rats showed low levels of neuritin gene activity, and all improved when treated with antidepressants.
But boosting the expression of the neuritin gene, and the neuritin protein levels helped just as much as the antidepressant treatment.
How can you boost your own brain levels of neuritin and reduce depression and anxiety?
Well, you can wait until a drug is developed that will do this.... or you can try other things that have been found to increase the plasticity of your brain. Brain training exercises have long been known to improve your ability to learn (no matter how old you are). This research now suggests that these types of exercises may also have a beneficial effect on your mood, via the boost they give to the hippocampus. (Remember that the hippocampus is a part of the brain that can develop new connections, which means new learning.)
So keep your brain active and try something new this week… even something very minor. Try a new food, start learning a new skill, or visit a part of town that is new to you… and notice how you will start to feel better, little by little.