Cortisol Stress Hormone Kills Brain Cells by the Millions
Conversely, we know that reducing cortisol levels with relaxation, increases the size of the hippocampus through neurogenesis.
Whenever a person is under stress, the stress hormone CORTISOL gets released into the bloodstream, which goes everywhere including the brain. More precisely, the mechanism goes like this... ARH (adrenocorticotrophic releasing hormone) is secreted by the hypothalamus. Cortisol harms and sometime kills brain cells in three ways: It interferes with brain's supply of glucose.
It interferes with the function of neurotransmitters. It causes influx of calcium into brain cells.
What Dr. Khalsa says about Cortisol and the Brain "Cortisol killed brain cells by the millions."
These were the words spoken by Dr. Dharma Singh Khalsa when he gave a talk about brain longevity at the Chautauqua Institution in New York state. Dr. Khalsa refers to the relationship between cortisol and memory as the "Cortisol Connection" in his book Brain Longevity. There he goes further to say that brains cells injured and killed could be in the billions. He writes ... "If you experience the stress response day after day, year after year, its toxic effects will gradually injure and kill billions of your brain cells."
"I am convinced, based upon my research and clinical work, that excessive cortisol production is one of the primary causes of death of those cells." Putting Things Into Cortex. It is scary to read that
a such large numbers of brain cells die. We have to keep in mind that this is over the course of a lifetime. That number is only a guess or estimation, because it is hard to image opening up a brain
to count the cells at the beginning of life and then at the end of life to compare. Since it is difficult for scientists to count brain cell lost while someone is still alive, it is difficult to say with certainty how much brain cells are lost on a regular basis, and scientist are continually revising their theories. In any case, it is still a good idea to maintain the survival of as much of your brain cells
as possible, and avoid excessive stress-induced cortisol which tends to kill them.
What Dr. Sapolsky says about Cortisol and Brain Dr. Robert Sapolsky is a neuro-biologist at Stanford University and author of the book Stress, the Aging Brain, and the Mechanisms of Neuron Death in which he writes about "how regulation of glucocorticoid secretion fails during aging, producing excessive secretion of these hormones, and how an only recently recognized consequence of that glucocorticoid ln excess is damage to the brain. Glucocorticoids are a class of steroid hormones in the body and cortisol is a main player among them. The book Stress, the Aging Brain, and the Mechanisms of Neuron Death is actually quite technical. Dr. Sapolsky wrote another book that is more geared for the general public that goes by the fun title Why Zebras Don't Get Ulcers. An article in "The Franklin Institute" says ..."The renowned brain researcher, Robert M. Sapolsky, has shown that sustained stress can damage the hippocampus, the part of the limbic brain which is central to learning and memory. The culprits are "glucocorticoids," a class of steroid hormones secreted from the adrenal glands during stress. "They are more commonly know as corticosteroids or cortisol."
Still don't believe that stress kills brain cells. See these references:
Page 137 soapbox titled "Brain Stress" in the book Beautiful Brain, Beautiful You says "Cortisol, the so-called stress hormone, has been shown in animal studies to actually kill off neurons in the hippocampus, the brain's memory center. Animals under chronic stress have smaller hippocampi, and there is reason to believe the same holds true for humans." Page 53 of "The UltraMind Solution" by Mark Hyman . "stress hormone cortisol injures the hippocampus, damages brain cells, and leads to memory loss and dementia.
Does Stress Affect the Brain By Karen Frazier
It seems human beings are under chronic stress these days. Stress, which is a biological imperative stemming from the fight or flight response that protected early humans from predators, has profound physiological effects on the entire body, including your brain. Even low levels of stress may cause significant changes in your brain over time.
Stress Shrinks Your Brain A 2012 Yale University study showed that chronic stress can actually reduce brain volume. In other words, if you are stressed out all the time, your brain just might shrink. Among its many effects, lower brain volume can lead to impaired cognition and hampered emotional function.
Why does this happen? According to the study, stress and/or depression activate a transcription factor known as GATA1, which regulates the genes that control synaptic connections. When fewer synaptic connections form, brain volume is lowered.
The good news is damage doesn't have to be permanent, however. Brain volume can return to normal, according to the author of a 2000 brain volume study of people with post-traumatic stress disorder. When hormone levels in the brain return to normal, brain volume rebounds to normal size.
Stress Kills Brain Cells, particularly in the areas associated with memory and learning, according to the Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, Rockefeller University. When your brain perceives stress, your body releases adrenalin into the bloodstream, giving your brain the burst of energy it needs to fight, flee, or freeze.
After about one minute, the adrenalin leaves your brain and it returns to normal function. If the threat persists or is severe, your brain calls in the big guns. According to Stanford University brain researcher, Robert M. Sapolsky, these are a class of steroidal hormones, called glucocorticoids. You may have heard of cortisol, which is one example of a glucocorticoid. These hormones remain in your brain, and continue to impact its functioning, far longer than adrenalin.
Both types of hormones head straight for the hippocampus. Your body requires a state of homeostasis (hormonal balance) to function properly. The balance between sympathetic and parasympathetic hormones is very delicate. Chronic stress can keep these hormones unbalanced. High levels of either type of hormones can kill cells in the hippocampus, hampering memory and learning.
Stress Hinders Cognition, Expression, and MemoryAccording to the University of Maryland Medical Center, stressful events activate the hypothalamic-pituitary-adrenal system, which release catecholamines - neurotransmitters such as dopamine, norepinephrine, and epinephrine. These chemicals activate the amygdala and suppress concentration, short-term memory, rational thought, and inhibition.
This suppression of normal brain responses allows you to engage fully in fight or flight without your brain intruding. Unfortunately, suppression of such responses over the long-term can also harm your memory and impair cognitive function.
Stress Depletes Brain Chemicals If a threat is especially severe or recurs frequently, such as protracted combat or living with abuse, the chemicals that carry messages from one nerve cell to another become depleted, and the brain becomes sluggish and inefficient. According to the American Institute of Stress, this can lead to a variety of mental health effects, including:
- Sleep disturbances
- Racing thoughts and difficulty concentrating
- Difficulty learning
- Difficulty making decisions
- Obsessive or compulsive behaviors
- Increased hostility, worry and guilt
Stress Surpasses Logical Thinking A man heroically rushes into a burning building to save a child, and afterwards says he "just reacted" or "went on auto-pilot." The HeartMath Solution, based largely on the research of Dr. Daniel Goleman, and presented at the 12th Annual Unified Program Conference, outlines what likely motivated the hero's actions.
He experienced extreme stress at seeing the child in imminent danger, and that information entered his brain with such force and urgency that it bypassed the prefrontal cortex and other higher brain centers. It went directly into the limbic system, which is the seat of emotion and reaction. Essentially his reason and judgment went off-line temporarily, and he reacted from the reptilian center of his brain, located in the brain stem. This is also the part of the brain that controls heartbeats, breathing and other autonomous bodily functions.
Interestingly enough, this is the same mental process that occurs during a crime of passion. When incoming perceptions bypass the rational part of the brain, a person may act without the regulating effect of wisdom, memory or judgment. Logic is simply unavailable in the moment, and reactions are based on raw emotion.
Stress Shuts Down Functions and Sharpens Others Have you ever encountered extreme stress and suddenly engaged in very instinctual behaviors? This happens because adrenaline causes the brain to start and stop certain functions in order to effectively deal with the perceived threat triggered by stress. According to the Franklin Institute, adrenaline will start and stop the following brain functions while it is present:
- It causes the brain to signal the release of glucose and fatty acids into the bloodstream in order to provide instant energy and strength.
- It sharpens your senses in order to perceive further threats.
- It makes you less sensitive to pain so you can continue your fight or flight.
- It shuts down functions unnecessary for either fight or flight, including growth, reproduction, or immunity.
- It instructs the brain to reduce blood flow to the skin.
Stress Compromises the Blood-Brain Barrier. The blood-brain barrier protects your brain and central nervous system from viruses, drugs and chemicals that enter your bloodstream. Multiple studies, including one printed in the British Medical Journal suggest that extreme stress compromises the blood-brain barrier, making it more permeable. This makes the brain more susceptible to infection and dangerous changes in brain chemistry.
If certain chemicals can easily permeate the blood-brain barrier, you may be more susceptible to nerve damage or even brain damage.
Gender Differences Men and women may respond to stress differently. According to the National Institute of Mental Health, women's stress hormone receptors are less adaptive than men's, so women may be more likely to experience stress related mental disorders like post-traumatic stress disorder (PTSD) or depression than their male counterparts.
Minimizing Negative Effects The news isn't all bad, according to Rockefeller University's Bruce McEwen, Ph.D. The brain's short-term response to stress is actually protective. However, over the long-term, stress can cause damage.
You can, however, take steps to reduce chronic stress levels and protect your brain. Engaging in stress-reduction techniques like meditation and regular exercise can help, as can maintaining a supportive social network. If chronic stress is a part of your life, try to find ways to minimize your stress load.
Managing StressIn his book, Why God Won't Go Away: Brain Science and the Biology of Belief, Andrew Newberg offers insights on how to manage stress:
- Relax and focus
- Breathe deeply
- Pray or meditate
- Do something that pleases you, whether it's listening to a child's laughter, going fishing or taking a bath
Healing Your Brain Strategies to facilitate healing include:
- Protect your brain by learning effective stress management techniques.
- Feed your brain. It is best able to withstand challenges when you eat a well-balanced diet.
- Kill the ANTS (automatic negative thoughts). Too many of those can trigger glucocorticoids.
- Exercise your body to boost your brain. Physical activity pushes blood and fuel into your brain, which helps you to reduce stress and improve memory.
- Visit your doctor early if you think you may have a brain problem.
Take Care of Yourself Understanding stress and its effects on your brain can help you protect yourself. In a very busy world where stress is the norm rather than the exception, it's important you seek to mitigate stress using any technique that works for you. Your brain manages all of your bodily functions, so it's important you protect it.