Stress Reduction (Part 1) - overview
Ryan Bradley, ND, MPH February, 2010
We all have and need stress. Without stress few of us would meet deadlines, perform optimally in any activity, or even wake up in the morning! This fact was recognized by Dr. Hans Selye in his 1956 book The Stress of Life, in which he coined the concept of the “General Adaptation Syndrome”. Dr. Selye recognized that “optimal stress” led to optimal performance, increased attention and focus and without any stress life would become boring and without emotion. Dr. Selye also recognized too much stress led to anxiety and unhappiness. In his book, he described phases of stress response, including the classic “fight or flight” response, or “alarm” phase, but he also recognized that chronic stress first leads to “adaptation” but ultimately leads to “resistance”. If the stress continues, Dr. Selye suggested the final stage occurs, or “exhaustion”. Although this model of stress also has some scientific support, it serves as an intuitive model of our experience with stress- first we respond, then we either adapt or resist, and then prolonged resistance typically wears us out!
The difficulty with Dr. Selye’s model is that everyone perceives stress differently. Activities like speaking in front of an audience are stressful for many people, but if well practiced, public speaking can be as simple as attending a meeting, or some other mundane element of a work day. Similarly, needing to perform advanced mathematics is not a desirable task for many of us, and even long division may cause some stress, however for an accountant or scientist it’s all just part of the job.
Further complicating matters is the response to stress is also very individualized. Some people improve their performance during stress and then crash into an exhaustive phase immediately. Some people respond outwardly and emotionally, seeking the help of their friends and family during stress. Others retreat inward, bottling up stress for their own internal processes. Some choose to eat their stress away, allowing the short term chemical response of feeling full with food to comfort them in times of need. Because different stimuli serve as “stressors” for different people, and then everyone reacts differently to their stress, i.e. stress is subjective, “stress” is very challenging for researchers to study.
If you have diabetes, you will clearly notice a change in your blood sugar (and often blood pressure) during times of stress. Why does this happen and can anything be done about it?
What is Stress?
Although many hormones participate in stress, stress is powered by three major hormones: epinephrine (AKA adrenaline), norepinephrine, and cortisol. All three of these hormones are produced by the adrenal glands, two small glands that sit on top of our kidneys in our lower back. Upon experiencing stress, our brain sends chemical messengers into our blood to cause the release of cortisol from our adrenals into our blood. Simultaneously, our nervous system directly stimulates the release of epinephrine and norepinephrine from our adrenal glands. Because several stress hormones are made and released by the adrenal glands, some practitioners refer to chronic stress as “adrenal fatigue” or “adrenal exhaustion”. These descriptors are useful when talking about stress with patients, but are not entirely accurate. True “adrenal exhaustion” can occur medically, and is a serious medical condition that requires hormonal treatment.
The release of epinephrine and norepinephrine is labeled a “sympathetic” nervous system response. This sympathetic response is in contrast to a “parasympathetic” response. You can think of the parasympathetic and sympathetic responses as the yin and yang of stress, where the sympathetic response is the classic “fight or flight” response, while the parasympathetic response is the “rest and digest” response. As suggested by these labels, each of these responses causes powerful changes in our entire body and to multiple organ systems.
The sympathetic stress response is designed to give our muscles the fuel they need to run, and to give our brains the fuel and mental clarity needed to perform in times of need. These effects are accomplished by reducing blood flow (and thus oxygen and glucose) to our digestive tract and away from our sexual organs and increasing blood flow to the muscles in our arms and legs, and to our brains in order to run away. This increase in blood flow requires an increase in heart rate, which results in an increase in blood pressure. In contrast, the parasympathetic response increases blood flow to our digestive and sexual organs, increasing production of stomach acid and digestive enzymes and increasing peristalsis, or the movement of food through our intestines. This response tends to lower heart rate and blood pressure as blood is more universally distributed throughout the body.
Cortisol and Blood Sugar
Another important hormonal player in our stress response is cortisol. Cortisol has several actions including being a potent anti-inflammatory hormone, thus the use of synthetic “steroid” injections for injuries, or inhaled “steroids” for conditions like asthma. (“Steroid” refers to the chemical structure of cortisone, and should not be confused with anabolic steroids like testosterone used illegally to increase sports performance; both share a similar “steroid” structure). Cortisol reduces inflammation by acting directly on our immune system and suppressing the immune response.
The other primary action of cortisol is to help maintain our blood sugar in times of starvation or deprivation. Cortisol helps to maintain, or can increase, our blood sugar by reducing our sensitivity to insulin. Thus more sugar stays in our blood stream for our brain and heart to use, but less sugar gets into our muscles and other tissues. Under normal circumstances, we all release a certain amount of cortisol in a daily pattern, or “circadian” rhythm.
The Dawn Phenomenon
For most of us the peak in this daily release of cortisol occurs at approximately 8 o’clock in the morning, but cortisol has been on the rise for several hours before this peak occurs. Cortisol is not the only hormone that is affected by this cycle, other hormones include testosterone, growth hormone, glucagon and epinephrine, and this daily hormonal surge is responsible for the “dawn effect” or “dawn phenomenon” that leads to high blood glucose in people with diabetes.
Why would we be designed to have this hormonal surge and increase in blood sugar in the morning? The simple answer is because we have to wake up! After an overnight fast, our brain needs fuel to wake up, observe our surroundings and look for food! Historically it was not as easy as opening the refrigerator door for breakfast! It is literally breaking our fast (breakfast) that stimulates the release of insulin, ultimately causing our morning cortisol spike to drop back down.
This reaction is thought to be why eating breakfast is an important element of preventing weight gain and maintaining normal blood sugar throughout the day; if the daily cycle starts poorly it just continues poorly throughout the day. This is also why people using insulin to control their diabetes may need higher doses at night to prevent large rises in blood sugars over night and in the morning.
Our Response to Stress
As mentioned, our response to stress begins, not surprisingly, in our brain. Our ability to respond quickly and robustly to threats has contributed to our evolution on this planet, allowing us to run from dangerous animals, and fight for our lives. When times were rough when we needed these responses, and we were programmed well to survive these tough times. This response has been, and may still be, critical to our survival. But is this response as critical now? Granted many people are still challenged in this world to meet their basic needs, but many of us (certainly most reading this article) are no longer threatened by vicious animals, major infectious diseases, or shortages of food or water. Instead the “stressors” have become more contemporary: our national financial crisis, family and relationship stress, workplace stress, manufactured deadlines, traffic, and long term health conditions. In fact, a recent review of the effects of cortisol on the body suggests that the stress responses that served us so well evolutionarily may actually be culprits in our modern diseases like obesity, high blood pressure, allergy, anxiety, depression and pain syndromes.1
The Effects of Stress on Body Systems
As mentioned, the hormones of stress have effects on numerous body systems. Chronic elevations of epinephrine and norepinephrine shift blood flow away from the digestive organs reducing digestive functions like enzyme production and nutrient absorption. Stress hormones may increase the permeability of the digestive tract to poorly digested proteins, leading to food intolerances. Stress seems to be important in even more extreme chronic digestive disease, like inflammatory bowel disease (IBD); patients with IBD had a greater cortisol response than patients without IBD and exposure to stressful events clearly cause flares in their condition.2
Stress hormones impact our immune systems too. Research shows that people under stress were less likely to form protective antibodies when given flu vaccinations.3 This reduced response is thought to be because “stress” reduces the activity of our anti-viral and anti-cancer arms of our immune system, favoring a more robust, but less specific response. Cortisol stimulates our immune system to make these changes by producing messengers, called cytokines, like TNF-alpha.4 TNF-alpha is a group of cytokines considered “pro-inflammatory”.
TNF-alpha has effects on our metabolism of other hormones, including our sex hormones, or androgens, like DHEA and testosterone. Specifically, TNF-alpha inhibits the formation of DHEA and testosterone and instead increases estrogen like hormones.4 This shift lowers sex drive, i.e. libido, and reduces metabolic rate. Because testosterone helps us maintain glucose-requiring lean muscle, a shift in testosterone production can increase blood sugar by reducing lean muscle tone, and thus metabolic rate.
Stress in Diabetes & Heart Disease
The basic physiologic action of stress hormones makes their relevance in diabetes and heart disease obvious. As previously mentioned, increased epinephrine and norepinephrine cause increases in blood pressure, and these increases can last for up to an hour after the stressful event.5 Cortisol clearly reduces our sensitivity to insulin, and thus raises blood glucose. Epinephrine and norepinephrine also stimulate our liver to make its own glucose (a process called gluconeogenesis) and release it into the blood stream, further increasing blood glucose. These hormones also cause the release of fat from fat stores, increasing blood fat and triglyceride levels. TNF-alpha is also known to reduce insulin production by the pancreas, and may contribute to the insulin deficiencies that occur later in diabetes. Increases in blood glucose that become too high, even in the short term, are known to result in increased oxidative stress and reduce the ability of blood vessels to expand properly (See Complementary Corner June 2009 for more information on Endothelial Dysfunction).
Does Stress Cause Diabetes?
Based on the above actions alone, it is not difficult to stitch together a theory of chronic stress causing diabetes and leading to heart disease. Although this hypothesis is complicated by other factors, including lifestyle factors and genetics independent of stress (although some argue many of our lifestyle choices are trained responses to stress, like emotional eating), this hypothesis does have some support in the evidence.
For example, a Swedish study in over 5,200 adults followed for 8-10 years demonstrated people with high emotional distress had twice the risk for developing pre-diabetes and three times the risk for developing type 2 diabetes than those with low distress scores.6 This study does not prove causation, but clearly demonstrates some association. Another example in heart disease is the vary large INTERHEART study in 52 nations in over 30,000 people that demonstrated psychosocial factors including depression, anxiety at work or home, history of a traumatic life event, and financial stress were responsible for over 30% of the population's attributable risk for having a first heart attack!7 (Also see Complementary Corner February 2009 for more on the role of depression in diabetes).
What Can You Change?
Although many of us hope for a time without stress, is this a realistic goal? Despite our efforts to reduce stressors in our environment (a process that I encourage, by the way) it may not be possible to remove them all - and remember without stress our performance suffers. So instead of focusing exclusively on the stressors, it is also critical to address our response! If the response to stress begins in our brain (it may not be all in our heads, but it does start there), then can our response to stress, or perceived stress, be re-programmed? Does lowering stress response improve blood glucose in diabetes? Reduce our risk for high blood pressure and heart disease? Can we reduce oxidative stress simply by changing our reactions?
One of the most important approaches to stress reduction is free, and relatively easy: breathing! For the sake of experiment, focus on your breath over the next few days/weeks. What is your breathing pattern like? Do you hold your breath unconsciously? Do you breath slowly or rapidly? Do you use your diaphragm to breathe fully into your belly or is your breath more shallow?
Breathing exercise - breathing slowly, fully and regularly - can be a simple and remarkably effective means of reducing anxiety, clearing the mind for mental work, and, yes, even lowering blood pressure and blood sugar. A typical exercise is to take just fifteen minutes to focus on the breath. Inhale deeply into the belly for a full count of 3 seconds, hold the breath for a full 3 seconds, and exhale slowly and regularly also for a 3 seconds count. An old yogic mantra states, “The mind controls the body, and the breath controls the mind”. Test this mantra in your own stress responses, and feel free to let me know how it goes for you.
In my next article I will summarize clinical research on more formal stress reduction techniques that can improve blood glucose and other risk factors. In the meantime, take a step back and assess your own stress and your response to stress. Which “stressors” are real and consequential? Which are perceived? Do you have responses to stress that are truly protective - or more detrimental - for your long-term health? Do you have stress reducing activities that you prioritize and do regularly? Are there patterns in your daily routine that could be changed to reduce the effects of stress on your body’s functioning? The answers to these questions have real consequences on your long-term health and happiness.
In Health- Ryan Bradley, ND, MPH
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2. Farhadi A, Keshavarzian A, Van de Kar LD, et al. Heightened responses to stressors in patients with inflammatory bowel disease. Am J Gastroenterol. Aug 2005;100(8):1796-1804.
3. Burns VE, Carroll D, Drayson M, Whitham M, Ring C. Life events, perceived stress and antibody response to influenza vaccination in young, healthy adults. J Psychosom Res. Dec 2003;55(6):569-572.
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5. Vlachopoulos C, Kosmopoulou F, Alexopoulos N, Ioakeimidis N, Siasos G, Stefanadis C. Acute mental stress has a prolonged unfavorable effect on arterial stiffness and wave reflections. Psychosom Med. Mar-Apr 2006;68(2):231-237.
6. Eriksson AK, Ekbom A, Granath F, Hilding A, Efendic S, Ostenson CG. Psychological distress and risk of pre-diabetes and Type 2 diabetes in a prospective study of Swedish middle-aged men and women. Diabet Med. Jul 2008;25(7):834-842.
7. Yusuf S, Hawken S, Ounpuu S, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet. Sep 11-17 2004;364(9438):937-952.