What You Should Know About How Stress Shapes the Brain
Daily hassles, poor lighting, health problems, unwanted changes in a relationship, work pressure, all of these can trigger stress. Acute stress, that is stress that is immediate, triggers a cascade of physiological reactions in the body that are all essentially designed to give us the extra energy and strength to respond to the stressor.
This stress-response can save our lives if we need to escape from a burning building or react quickly to an oncoming car. But, when stress is chronic, the emotional and physiological impact on the body can be devastating.
And stress affects not only our emotional and physical well-being, it also affects how our brains function. Humans are not alone in their stress-response. Researchers often look at animals to better understand the wide range of changes that occur in our bodies and brains when under stress.
Researchers have found that when animals are exposed to prolonged stress they develop physical and mental problems including, high blood pressure (hypertension), loss of appetite, weight loss, muscle wasting, gastrointestinal ulcers, loss of reproductive function, suppression of the immune system, and depression. These are the same physical and mental problems stress contributes to in humans.
And unfortunately, we don't assimilate or adjust when we experience stress. Instead, with increased stress, we become increasingly sensitive to stress. So, if you're stressed by pressures at work, you're more likely to experience noisy kids at home or traffic as stressful. In essence, under chronic or prolonged stress, your threshold for tolerating stressful events is lowered.
What's this all got to do with the brain? Researchers are now suggesting that heightened levels of stress actually rewire the brain. This rewiring promotes continual and habitual cycles of stress (Dias-Ferreira and colleagues).
In research conducted on rats, a study found that stress caused structural changes in parts of the brain including atrophy in the area of the brain associated with decision-making and goal directed behaviors. The rats under stress began to respond to stressors habitually, rather than on an evaluation of their consequences.
What does this mean? When we're under stress our attention tends to narrow. We take in less information and we are less flexible in our responses to stressful situations. Our ability to evaluate consequences of our actions and to choose from an array of possible responses diminishes.
It can be disheartening to imagine that stressors are changing our brains and actually wiring us to be more stressed, but hope is not lost. The brain can re-wire to experience continual and habitual cycles of stress, but it can also rewire in a positive direction and scientists have discovered at least in part how to do it.
Neuroplasticity is a term used to describe brain changes that occur in response to experience. Under stress, the brain changes in ways that tend to contribute to additional stress.
However, scientists are finding that meditation can rewire the brain in ways that decrease our experience of stress.
Sara Lazar, Ph.D, an instructor at Harvard Medical School, conducted research investigating the impact of meditation on brain structure. Her research found that "meditation may be associated with structural changes in areas of the brain that are important for sensory, cognitive and emotional processing. The data further suggest that meditation may impact age- related declines in cortical structure."
Richard Davidson, a neuroscientist and leader in the study of the affects of meditation as director of UW-Madison's Center for Investigating Healthy minds, suggests that systematic meditation practice can act like an antidote to affects of stress on the brain. Meditation may not only calms the body, it may also improve our ability to engage in analytical thought.
When under stress, sitting still and focusing your mind might feel like the last thing you want to or are able to do. But this practice, of paying attention to one thing at a time, in the present moment, may be just what the brain needs to renew healthy functioning.
Dias-Ferreira, E. et al. (July 31, 2009). Chronic Stress Causes Frontostriatal Reorganization and Affects Decision-Making. Science: 621-625. [DOI:10.1126/science.1171203]