Hormonal Update Volume 2 Number 11

Stress Creates Distress for Your Mind

Hormones and the Brain, Part 2

To help you cope with life’s stresses, your body has certain built-in hormonal mechanisms in place. Stress hormones help send energy where it’s needed in the body during an emergency. They also help regulate less important bodily functions during a crisis. Think of it like this — when you leave for work in the morning you generally turn off your electrical appliances and lights. This is because you are not going to use them while you are away. In a similar fashion, when the body is responding to stress it turns off certain energy consuming processes like digestion, reproduction, and even immunity in order to respond more fully to the sudden onslaught of physical or psychological stress. 

When the body evaluates what it needs during stress it asks, ‘do it now, or do it later?’ Why make sperm or ovulate if you are trying to navigate a boat in suddenly rough seas? At that moment you need all of your reserves to cope with the situation at hand. Does your immune system need to be at peak performance if you just got fired from your job? Not right away. When you are under stress, these processes come under the ‘do it later’ category. 

The important ‘do it now’ processes that the body summons during times of stress include increasing energy and strength and improving brain function. During an emergency you need to hear better, smell more sensitively, and gather and process information more quickly. Stress hormones have a powerful influence on the brain, playing a very important role in modulating both emotional and cognitive function. They help insure that you have all the mental faculties you need to cope with the ups and downs of life. 

This is the good news about stress hormones. The not-so-good news is that when it comes to stress hormones more is definitely not better. As necessary as these hormones are, excess amounts have long been recognized to cause disease. Excessive stress hormone levels can trigger many stress related conditions, including high blood pressure, blood sugar problems, fat accumulation, compromised immune function, exhaustion, bone loss, heart disease and, we now know, memory loss. Everyday stress can bring on minor memory failures and temporarily alter the ease and speed with which the brain retrieves and processes information. Relentless, extreme, or long-term exposure to stress hormones can actually damage and shrink the brain. 

Using new imaging techniques, researchers have found that some Post Traumatic Stress Disorder patients have about 25% atrophy in the hippocampus region of the brain. The hippocampus is the part of the brain used for processing and storing information. It is crucial for proper cognitive function and emotional well-being. Losing twenty-five percent of this region of the brain is similar in impact to losing one of the four chambers of the heart. 

The Stress Response

First, what exactly is stress? A simple way to look at stress is that it is anything that challenges the homeostatic balance of the body. This homeostatic balance includes ideal body temperature, proper ph of the bloodstream, optimum blood sugar and pressure levels, even a proper ratio of bone building to bone remodeling. Stress can be anything that upsets this balance.

Your stress response helps you “fight the tiger” during stressful situations. By increasing blood sugar levels, heart rate, and even improving cognition, your stress response helps you get up and get going. It is regulated in part by two hormones, cortisol and DHEA. 

Cortisol is a glucocorticoid hormone, secreted by the adrenal glands. In the morning, about two hours before you wake up, the release of cortisol into your system naturally begins to increase. Your blood pressure and heart rate go up, which provides you with the energy you need to gear up and greet the day. Then, gradually, as the morning progresses, cortisol levels decline. This is normal. 

Cortisol is also released into your system in response to stress. Within seconds of a perceived emergency, cortisol floods your system in attempt to provide you with the resources you need to respond to the situation. 
DHEA, also an adrenal hormone, functions more as the recovery specialist. Once the stressful situation has passed, DHEA helps restore a sense of calm and bring your body back into balance. DHEA promotes a healthy stress response, has been shown to be neuroprotective, and to enhance memory. Its antioxidant properties may help protect your brain from free radical damage. 

Under normal conditions cortisol and DHEA work together as a kind of stress management partnership. However, when you are under continual stress, and your adrenals are forced to continually pump out these stress hormones, these important glands can become exhausted and the natural restorative balance between DHEA and cortisol can be interrupted. With DHEA in short supply, the damaging effects of excess cortisol can go unchecked. 

DHEA has been shown to improve brain function and cognition, ensuring a better response to new information and an increased capacity to remember what you have learned. Brain tissue has five to six times as much DHEA as other tissue in the body. People with Alzheimer’s disease have DHEA levels that are half that of healthy people of the same age.

Mounting Evidence

With its abundance of cortisol receptors, the hippocampus is the part of the brain most sensitive to this hormone. Cortisol actually improves memory when it circulates briefly through the brain. However, the reverse is true when cortisol levels stay elevated for long periods of time. Patients with chronically high levels of cortisol show accelerated degeneration of the hippocampus, the brain region crucial for proper cognitive function and emotional well-being. This is similar to what happens with severe diseases of the brain, like dementia and Alzheimer’s. As these diseases progress, the all-important hippocampus atrophies.

There is mounting scientific evidence suggesting that stress upsets the normal secretion patterns not only of stress hormone, but other hormones as well. This can have both short and long-term effects on brain function and health. In one salivary hormone evaluation, scientists measured hormone levels in military personnel on the day after they performed all night duty. Researchers found that cortisol was elevated the afternoon after the sleepless night. The body seemed to release more cortisol in an attempt to stay awake. These findings are significant as they may underscore the side effects of chronic sleep deprivation - excessive fatigue, mood deterioration, and poor concentration. And, in fact, these hormonal imbalances may have a more permanent effect on the physiology of the brain.

Chronic jet lag has also been shown to disrupt the natural circadian rhythm of the body and trigger elevated cortisol levels, which in turn can erode part of the brain. Flight attendants who had only brief rest stops between international flights were found to have higher cortisol levels and decreased volume of the right temporal lobe in the brain (as measured by an MRI). This was not true of flight attendants with longer than five-day layovers between international flights. This research links high cortisol with degeneration of the hippocampus. Scientists are now suggesting that proper rest and recovery time may be imperative in protecting the health of the brain. 

Another study showed that women who suffer depression and chronic stress also had high cortisol levels and significant atrophy in the hippocampus. Newborns who suffer great stress just after birth also show mental impairment, including memory deficits. Over the long run, it appears that their brains actually age faster than those of newborns who do not experience severe stress.

Keeping Tabs on Your Stress