Montana State University-Billings
Department of Health and Human Performance
HHP 436 Stress Management and Emotional Health
Spring 2007
Instructor: Ernesto (Ernie) A. Randolfi, Ph.D.

The Psychophysiology of Stress Part I


Its not stress that kills us, it is our reaction to it. - Hans Selye


Think of a situation in the past month when you felt really stressed, angry, anxious, or fearful. Now close your eyes for a few moments and try to remember as much about that situation as possible. With your eyes closed try to remember exactly what your body felt like at that time. Use all your senses and focus on your entire body what physical changes were evident?

Chances are you may have experienced some of the following symptoms: rapid shallow breathing, pounding heart, tight muscles (including fists, jaw, neck), stomach upset, nerves on end. The easiest way to understand why these physiological changes occurred is to understand what Cannon (1914) termed the fight or flight response. When men and women were first put on this earth there was a constant struggle for survival. A survival of the fittest, as Darwin would explain it. If you were one of these prehistoric people and you encountered a bear on the path you had essentially two choices: you could either instantly run away or fight. The people we evolved from were very good at doing one of these two things (if they were not, they usually didn't get a chance to reproduce). As men and women go about their lives, daily chance encounters with wild bears are rather remote (unless you live and are employed in certain areas of Montana), however our evolutionary conditioned response to stress is still with us. The difference today is that many of our stressors are psycho-social in nature.

Physiologically the response is still the same even though we do not have the same sociological choices. If your boss comes crashing into your office, bangs his fist on your desk and screams, "This report was supposed to be in my hands by yesterday! If I don't have it by 3:00 your fired!", that can be very stressful. You may not have the option of punching him in the face or running away, but that is what your body is getting ready to do. If you experience encounters like this on a daily basis you may be heading for some problems.

Approximately 1500 biochemical reactions occur every time you experience stress. Various organ systems go into overdrive and prepare to take action. If no action is taken the byproducts of the stress response continue to circulate in your body for hours and sometimes days. Various organ systems may start to falter, lets take a closer look at what is happening at these organ systems.

The Cardiovascular System

The heart and circulatory system is very important in the stress response, think for a moment why this is. When you see that bear on the path why does your heart beat faster? Why does your blood pressure increase? Why do your blood vessels on your peripheral areas (skin, hands and feet) and your brain vasoconstrict and reduce blood flow while other organs like your large muscles vasodilate and increase blood flow? The conditioned fight or flight response offers a ready explanation.

Your heart is beating faster and stronger (increased stroke volume) to get more oxygen and nutrients to the areas of the body where it is needed (like the large muscles) so you can fight and run away. A vasoconstriction occurs on the skin surface, the digestive system, and to the brain so more blood can flow to the needed areas. If more blood is going into a smaller area at a faster rate that causes your blood pressure (the pressure exerted against the walls of your arteries and veins) to increase. The vasoconstriction on the surface may also help if you are injured so that you will not bleed as much. The brain doesn't have as much blood flow possibly because you don't need to be doing a whole lot of heavy duty thinking to be able to run away from a bear.

This all sounds pretty good, so what is the downside? The problem again is that we don't really need to physically fight bears anymore. All this action on the cardiovascular system caries a toll, especially for certain types of people. Some people due to their genetics, lifestyle, or past medical history seem to have their cardiovascular system impacted by stress more than others. Some people are cardiovascular reactive, when exposed to stress their system goes into hyperdrive and stays that way for long periods of time (hypertensive). The emotion most responsible for this action seems to be anger and hostility. Those who are easily angered or have continual seething hostility are at most risk for developing heart disease. The high demands on the heart muscle is one reason for heart disease being the number one cause of death in the US, we will look at some others later.

In addition to heart disease other circulation related disorders can occur, e.g., migraine headaches and Raynaud's syndrome. Raynaud's is an interesting condition and you may know someone who has this problem. In this condition, the vasoconstriction of blood vessels in the hands and feet is so severe victims feel extreme cold and pain in their fingers and toes. Precipitated by stress, we will discuss how to treat this and migraines using some simple forms of biofeedback later.

By the way, a shunting of blood to the brain during stress may be one of the reasons folks have difficulty remembering things when they are stressed. Test Taking Anxiety: Did you ever study really hard for an exam and then were not able to remember simple facts during the exam. Often when students leave the exam room and finally relax the information comes right back to them.

The Digestive System

An explanation of what happens during stress to the digestive system is easy, it generally shuts down. It is not necessary to be digesting food if you are running away from a bear. Changes in mucosal lining of the stomach, decreased peristalsis (rhythmic muscular contractions) of the stomach, small and large intestine, and decreased salivary secretions are all effected by emotions. Ever notice how your mouth goes dry if you have to give a speech in front of a group?

While it may be important to conserve energy in times of distress and provide energy to priority areas, a number of problems can arise from over stress, or for those who are prone to digestive disorders. Acute complications include nausea and vomiting. Some describe the sensation of butterflies others retch from the symptoms of sever stress. Chronic stress is related to constipation, ulcers, and even hemorrhoids. Some studies have found that the absorption of nutrients by clinically depressed individuals is impaired. Even if you are eating a healthy diet you may not get the same nutrition out of your food as someone else eating the same food.

Respiratory System

If you are running away from a bear you would like to be able to get as much oxygen into your blood as possible so your respiration increases and your bronchial tubes dilate. In the severe anxiety of a panic attack some individuals will become dizzy and pass out from hyperventilation. Paradoxically other individuals respond to stressful circumstances by experiencing the frightening condition of asthma were bronchial tubes severely constrict. This is in part, a response to activation of the parasympathetic nervous system (to be discussed later) and is similar to what occurs in a small percentage of people who experience diarrhea in response to stress instead of constipation.

Skeletal Muscular Contraction

If you watch a cat or dog when they are frightened you can see their muscles tighten in response. An encounter with a bear would probably have lots of your muscles contracting. The logic is simple, if you need to spring into action your muscles need to be ready, hence the tension. Unfortunately, some people are always ready to the point where they cause themselves pain. Ever notice when studying hard late at night, or after staring at your computer screen for hours that your shoulders are up by your ears. Or better yet, watch people in cars trying to hurry through traffic, you can see what I call the white knuckle syndrome as they squeeze that steering wheel. It is as if this will some how allow them to reach their destination sooner. For those prone to muscular tension we see increased rates of tension headaches, low back pain, temporal mandibular joint syndrome (TMJ), and grinding teeth.

The Liver

Lots of stuff is happening in the liver in response to stress. Glycogen is turned into glucose, fats and cholesterol are dumped into the blood stream and proteins are metabolized. The reason for all this is so you can continue to supply energy to your muscles as you run away from that bear. If you don't run or fight all this junk continues to circulate in you blood stream creating some potential problems.

For those with diabetes that are not very good at breaking down the blood sugar glucose stress complicates their condition. A corresponding increase in protein metabolism means that proteins used for energy are not available for the development of white blood cells and antibodies which are necessary to fight infections.

In addition to the above two nutrients, the high levels of fat and cholesterol circulating in your blood is associated with heart disease. Cholesterol is made up of lipoproteins, some of which stick to artery walls (atherosclerosis) that were damaged by the high blood pressure (atherogenesis) discussed earlier. As the arteries narrow they also calcify and harden (arteriosclerosis) further increasing blood pressure and the strain on coronary arteries.

Narrow inflexible arteries are much more prone to blood clots which are likely to increase due to an increase thrombin from the liver's store of prothrombin. Thrombin is released in response to stress and helps your blood thicken and clot, which is real important if the bear should take a swipe at you. Individuals who suffer heart disease often have much more viscous (thicker) blood. This is one of the reasons it is a good idea for middle aged and older folks to take a simple anticoagulant like aspirin once a day. Better yet don't get stressed out.

Other Organ Systems

In response to stress the spleen increases the production of red blood cells (to carry more oxygen?), kidneys decreases urine production (so you have more fluid to transport blood cells), sweat glands release more fluid (to dissipate heat), thyroid gland produces thyroxine (elevates metabolism, lasts for days and keeps you awake to survive), pupils dilate (to let in more light so you can see better), hearing becomes more acute (so you can hear that bear chasing you).

Lots of other reactions are occurring at end organs, but the important concept to understand is that all of this is happening for a reason. Originally that reason was survival. In the case of occupations where workers need bursts of physical activity such as fire fighters or professional athletes this stuff is still crucial. It may not be as important for others and for some it is potentially harmful. Understanding this is the first step in managing stress.


Symptomatic Response To Stress



The mind is its own place, and in itself, can make heaven of Hell, and a hell of Heaven." - John Milton


Circulatory System

Increased Heart Rate

Increased Stroke Volume
Increased Blood Pressure
Vasoconstriction On Skin Surface And Brain
Vasodilation In Muscles And Some Organs Respiratory System

Nasal Passages, Throat And Bronchi Dilate

Respiration Faster

Liver

Glycogen Into Glucose

Proteins Mobilized
Fats In Bloodstream
Prothrombin Into Thrombin

Gastrointestinal

Decreased Peristalsis And Digestion

Decreased Salivary Secretion

Also

Spleen Increases Production Of Red Blood Cells
Thyroid Gland Produces Thyroxin
Pupils Dilate
Hearing Becomes More Acute
Sweat Glands Are Stimulated
Thymus Glands And Lymph Nodes Decrease Lymphocytes
Kidney Decreases Urine Output
Bladder Relaxes
Voluntary Muscles Contract (Bracing)
Endorphins Are Released


The Psychophysiology of Stress Part II


I'm an old man and I've had many troubles, most of which never happened. - Mark Twain


As scary as it may seem, we need to begin by discussing the master organ: the brain. In order to have an emotional and physical reaction to stress, some perception and appraisal must occur. The senses (vision, hearing, touch, taste) or our memories must supply input to our higher brain (neocortex) for appraisal to take place. The stressors whether: Biological (toxins, heat, cold) Psychological (self-esteem, depression) Sociological (relationships, societal expectations), or Philosophical (purpose in life, how you spend time) require some level of cognition.

Stressors can be both real and imagined. To demonstrate this in class I have students close their eyes and sit very quietly. I then take a large book and slam it on a table as I scream. Although cruel this is fairly effective at eliciting a stress response. I quickly explain how their hearing picked up on the message I was supplying and brought this information to the cortex. The cortex communicates with other areas of the brain and instantaneously send a message to the heart to start beating faster, to muscle to begin to tighten and a bunch of the other organ systems. The brain then quickly analyzes the situation to determine if there is any danger from the sound, if not they will quickly calm back down. If student can convince me that they understand this process, I then ask them to humor me by being still with their eyes closed one more time. After they stop protesting they eventually get quiet again but with a noticeable difference. They cannot hide their apprehension, it is apparent in their body language. Foreheads are wrinkled, jaws are tight, fists are clenched in anticipation. After letting them wait for a bit, I then ask them to open their eyes as I explain that I do not have to do anything in order cause them to feel stress. They are capable of creating stress through their own worry and imagination of what might happen.

To break down this process further, it may be helpful to think in terms of four levels of stress message systems or pathways. The cortex of your brain communicates with mid section of your brain (in this case the thalmus) through what is called the reticular activating system (RAS). Communication is through chemical neurotransmiters which are also used by the thalmus to communicate with the hypothalamus (refer to the diagram on page 20 of your text). The hypothalamus can be divided into posterior and anterior sections and this is where the discussions of pathways begins.

Pathway 1 (elapsed time: 2-3 seconds, duration: seconds)

The posterior portion of the hypothalamus controls the activation of the Autonomic Nervous System (ANS). The ANS is that part of your nervous system that controls all the automatic operations of your body (like food digestion and breathing). Aren't you glad you don't have to remember to breathe all the time? If we did, we would die as soon as we fell asleep. The ANS is divided into two separate channels (see figure on page 29 in your text): the Sympathetic branch (the Gas) and the Parasympathetic branch (the Brake). In response to stress the sympathetic nervous system delivers messages down your spinal cord to various organ systems, telling your heart to start beating faster and stronger, telling your lungs to increase respiration, telling muscles to brace, etc.. This pathway works very quickly, but the effects are very short term. If the stressor is gone, or if you just think of something else the neocortex sends a message to the hypothalamus to stop the process. Stopping requires the parasympathetic system to activate nerves that slow down the process and return to homeostasis.

Pathway 2 (elapsed time: 20-30 seconds, duration: minutes)

In response to stress the posterior part of the hypothalamus also sends a nerve impulse directly to the center of the adrenal glands that sit on top of your kidneys. This causes the adrenals to secrete epinephrine and norepinephrine into the blood stream. Epinephrine and norepinephrine are also known as adrenalin and noradrenalin. By the way, epinephrine is the substance that they inject directly into the heart during heart attacks on TV medical shows. These two chemicals are the body's natural speed. They are the same chemicals that are delivered at the end of nerves in pathway 1 to turn on organs. When the blood carrying these compounds get to target end organs, this is what causes those organs to turn on to hyperdrive. Because this process requires the circulatory system to deliver the goods, it takes a bit longer to get to organs. The effects last until all the epinephrine and norepinephrine is used up.

Pathway 3 (elapsed time: 1-2 minutes, duration: hours)

The anterior hypothalamus upon stress activation releases a compound called Cortiotrophin Releasing Factor (CRF) that stimulates the Pituitary Gland to secrete Adrenocortropic Hormone (ACTH) into the blood system. ACTH circulates around to the outer portion of adrenal glands where it stimulates the release of cortisol and aldosterone (other hormones are released, but are not as important, besides I'm trying to keep this simple). Cortisol in addition to other effects causes the liver to release fats, glucose, protein and cholesterol. Cortisol is often referred to as the Ƭstress hormoneƮ, it provides the fuel to allow us to continue running away from bears. It is also responsible for interfering with the production the immune system components (Leucocytes and antibodies). Aldosterone is one of the hormones that helps your body retain sodium, which keeps more water in your blood, increasing blood volume and pressure.

Pathway 4 (elapsed time: 1-2 minutes, duration: hours)

The hypothalamus working with the pituitary gland also releases vasopressin (ADH) and oxytocin. Delivered into the blood system these hormones primarily work on controlling the level of blood pressure (through smooth muscle contraction and water retention) in your body so that muscles and another important organs can get the oxygen and nutrients they need under stress. Anti-hypertension medications often work to interfere with these hormones so the levels do not stay elevated in individuals with abnormally high blood pressure.

Pathway 5 (elapsed time: hours, duration: days)

The final pathway to be discussed is also from the anterior hypothalamus and involves the release of Thyrotropic Hormone Releasing Factor (TRF) to the pituitary gland. The pituitary produces Thyrotropic Hormone (TTH) that is dumped into the blood stream and stimulates the Thyroid Gland to produce Thyroxine and Triiodothyronine. Thyroxine and Triiodothyronine work to increase the basal metabolic rate (BMR) from 60-100%. In doing this there is an increase in free fatty acids, gluconeogenisis, gastrointestinal motility, respiration (50-60 breaths/minute), heart rate, blood pressure, and cerebration. Cerebration (an increase in mental activity) is evident when you are exhausted lying in bed trying to get to sleep and your mind is going a mile a minute. Its like you are watching bad movies in your head playing everything you did that day and will do tomorrow, over and over again. These hormones are helpful in that they decrease fatigue so you can keep running away from bears for days (real or imagined).

I hope you can appreciate the coordinated complexity of these pathways as they automatically occur in your body hundreds of times a day. An important concept to understand is that although these came about as a conditioned evolutionary response to prehistoric survival, all of this is under our voluntary control through various stress management strategies. Whether or not one chooses to take the time and effort necessary to learn the techniques is also a voluntary choice.