Your Brain on Stress

Have you ever had the experience of everything around you seem to fall apart? It could be deadlines looming, holidays happening, or end of year approaching. It becomes so much more difficult to wrap your head around what you need to do to get through this. Why is it so difficult? Let’s take a look at how stress hijacks your brain and makes everything tougher to get through.

Stress Effects on Memory

Let’s first take a look at the effect of stress on memory. The chronic stress cycle has cortisol staying way too long in your brain. Even though it initially put you into fight or flight mode and helped your brain be more effective, on a long-term basis it can kill brain cells. That is definitely not a good thing. Researchers from the Yale Stress Center found that chronic stress can reduce brain volume (cells dying) and a decrease in brain function in otherwise healthy individuals. They found that stress can hurt you now by decreasing the amount of gray matter, but it can also make it more difficult to manage stress in the future. The continual release of stress hormones adversely affects brain function, particularly memory. Robert M. Sapolsky, a renowned brain researcher, found that chronic stress can damage the hippocampus (center for learning and memory). Here are some specific brain functions that stress interferes with.

The Prefrontal Cortex – First Stop in Fight or Flight

One of the primary duties of stress hormones in a threatening situation is to divert blood glucose to the exercising muscles. In doing that the brain’s prefrontal cortex does not get the amount of glucose (energy) it needs to function in its memory duties. The prefrontal cortex is the first stop in the fight or flight pathway. It has a finite amount of energy to perform its duties. When glucose is diverted to muscles, the prefrontal cortex does not get the sustained nutrients it needs for energy and depletes quickly. Working memory (short-term) is then short circuited. Working memory takes the information in and sends it to the hippocampus for memory consolidation and embedding. When working (short term) memory cannot get the information to the hippocampus, then memories are not created and stored. This phenomenon could explain why people have a hard time remembering a traumatic event and why short-term memory is usually the first casualty in age-related memory loss due to a lifetime of chronic stress.

Cortisol – the Disruptor

Cortisol also hinders the function of neurotransmitters – the chemicals the brain cells use to communicate with each other. Excessive cortisol makes it difficult to think or retrieve long-term memories. There are people who get confused in a severe crisis mainly because their mind goes blank because of excess cortisol and they cannot retrieve long-term memories. These memories can be just general knowledge of how to get out of a building for example.

What else happens to the hippocampus when there is excessive cortisol present? During the stress cycle, the hypothalamus sends out the signal for cortisol to be produced. When the proper feedback loop is working, the hippocampus tells the hypothalamus to stop sending the signal for more cortisol. But, the hippocampus is the area most damaged by cortisol. Dr. Dharma Singh Khalsa writes how older people have diminished volume in their hippocampus, in the tune of 20-25% loss of their cells. This deficit prevents the hippocampus from providing the proper feedback to the hypothalamus, so cortisol continues to be produced. Then the increase of cortisol in the hippocampus does even more damage and results in even more cortisol being secreted. It is a very dangerous cycle and can be difficult to stop.

Aging Brains Are More Vulnerable to Stress

Aging brains are more vulnerable to the effects of stress. Stress hormones actually increase as we get older. They inhibit neurogenesis (new cell growth) in the hippocampus. When healthy older adults who were not impaired by stress were tested, it was found that neurogenesis in the hippocampus continued. With cell loss happening in the hippocampus due to high cortisol output it is thought that these processes are responsible for age-related memory deficits. (As if we needed something else to stress over!) However, our miraculous brain is able to reverse these deficits with stress interventions.

The Difference Between Men and Women’s Response to Stress

There is a difference between men and women and how they react to stress. Women are more drawn to the tend and befriend model. This means that instead of going after the stressor aggressively, women call friends and find comfort in groups. This action dates back to our primitive ancestors when the men in the group went out to protect the group while the women stayed behind and took care of the children. They developed alliances within the group to help offset threats. This protected them from the continual fight or flight response.

Men are at more risk from stress. They are more vulnerable to the adverse health effects stress brings. They are more apt to develop certain stress –related disorders such as hypertension, aggressive behavior, or abuse of alcohol or hard drugs. Because men would prefer to be alone after a stressful day, they do not release their stress in an effective manner.

There is one more difference between men and women and stress. Oxytocin is a hormone secreted by both men and women in times of stress. This hormone has a calming effect which results in less anxiety. Male hormones reduce the effect of oxytocin but the female hormone estrogen amplifies it. Research to affirm this has been extensive.

Bottom Line

Bottom line – stress plays havoc with our brains and has catastrophic repercussions throughout our brain and body. But we are blessed with amazing brains. Despite the damage that cortisol does to our brain, if we lower our stress levels and stop the chronic stress cycle, our brains will start to reverse the damage. Again, we have the control to change things – even the effects of stress.

References:

Sahlberg, J. (January 17, 2012). Stress causes brain shrinkage, Brain in the News, Dana Foundation. February 2012.

The Human Brain. Retrieved June 28, 2013 from http://www.fi.edu/learn/brain/stress.html