Once upon a time, when humans had to fight off attacking barbarians, their bodies developed a system to divert all energy and focus to the muscles during periods of extreme stress. The biology was simple—when there was danger, the body would produce certain chemicals such as cortisol and epinephrine to shut off areas of the brain needed for higher levels of thinking and memory, and divert all energy to the muscles for the “fight or flight” response. This system worked very well, and the human race survived to eventually live in relative safety in modern times. The biological “danger” response remains, and though the dangers have evolved, the body’s reaction to stress has not. This is why people tend to forget things when under pressure, and explains why victims of trauma often cannot consciously remember what happened. It is also why police officers and the military train their maneuvers and methods over and over again, so that they become a part of what is called their “muscle memory”—taken out of the realm of the prefrontal cortex and hippocampus, and engrained in the parts of the brain that have been evolved to kick into overdrive under dangerous circumstances.
Studies over the years have shown that on a short-term basis, stress and the cortisol reaction are not harmful to humans. As a matter of fact, some scientists believe that short periods of stress can actually help memory as the cortisol and epinephrine sharpen focus. However, if stress persists over time, or if a body is repeatedly subjected to it, the effects can be devastating. The chemicals that are produced to help the body think fast, fight hard, and flee quickly, are meant for short term use, and if the stress, or perceived danger, doesn’t go away, the brain keeps on pumping those powerful drugs into the blood. Long term, these substances are toxic and can permanently damage the hippocampus and the prefrontal cortex—two parts of the brain that are responsible for memory and learning. What is worse, the hippocampus is also the part of the brain responsible for regulating the release of cortisol, so as it deteriorates, the body loses the ability to shut off the very chemical that is now damaging it.
Stress is a part of daily life. So what can be done to offset the damage that it is doing to the brain and specifically the memory? The first, simplest, and most seemingly impossible task is to reduce the stressful events that are causing the overload in the first place. Often a person’s own behaviors and habits increase the amounts of stress they put themselves under. If any of these stressors can be removed, the body has that much less perceived danger to deal with. It can be as simple as leaving for work earlier so as to not have to chase the bus down the street in the morning. Secondly, methods such as yoga, meditation, and prayer are shown to lessen the stress reaction in the brain as the body becomes calm. Changing the way the mind and body perceive stressful events by consciously relaxing during or directly after those events can help to condition the hippocampus to dump less cortisol into the blood. Learning to deal with chronic stress, and letting go of baggage that lingers and presses those emotional danger buttons after the events have passed, can help break the dangerous cycle of cortisol and epinephrine overload and save the brain’s memory centers from deterioration.
Life is full of stress. The human body is a marvel that has long known how to adapt to whatever dangers are placed in its path. In modern times, the body reacts to stressful events much the same as early human bodies reacted to more life-threatening stressors. The difference is that in this day and age, the stress is less dangerous, but more chronic—and the damage to the memory centers of the brain can be its own danger. By being aware of the link between stress and memory loss and by taking steps to manage the cycle, modern humans can preserve their brain—and their memories.