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How Your Heart is Affected by Stress
24 September 2007
Help! I'm stressed out!
We've all been there – whether it's job-related stress, personal stress, or stress from having too much schoolwork. Everyone has some aspect of their lives that overwhelms them at times; what people don't know is how stress can cause a cascade of events that affect them both physically and emotionally. Stress itself is basically how a person reacts to their physical, emotional, environmental, or chemical surroundings. What many people don't know is that stress can be physical or emotional, and it can be felt in different amounts in different ways (http://www.americanheart.org). Stress can manifest itself in many different forms from events such as illness, death of a loved one, relationship problems, new jobs, heavy workloads, financial concerns, pregnancy, perfectionism, and a whole list of other significant physical or emotional changes called stressors (http://www.webmd.com). An important correlation has recently been developing between environmental and psychosocial factors, stress, and cardiovascular disease – the leading cause of death in the United States.
So, how does this work? How does stress disrupt cardiovascular health?!
According to several sources, stress is actually not an independent factor. In fact, stress actually affects certain behaviors that are high risk factors for heart disease, such as smoking, overeating, or lack of exercise. People actually respond to stress in many different ways. Everyone's different; some people tend to make a bad situation worse by responding with guilt, anger, sadness, or anxiety. Other people can cope with stress calmly without these harmful responses (http://www.webmd.com). One form of stress, physical stress, can be harmful in certain situations; but it is important to note that physical stress cannot actually cause cardiovascular disease. Rather, it can be harmful for those who already have heart disease in certain instances. Exercise can place increased demands on heart muscle that is already weak, which causes the heart to become ischemic (starved for oxygen), which can then cause angina or a heart attack (death of cardiac muscle) (http://heartdisease.about.com/).
Generally, when under any type of stress, the heart just has to work harder. When under stress, adrenaline is released, which instigates the "flight-or-fight" response, increasing blood pressure and heart rate, causing the heart to become ischemic. When this happens, the already narrowed arteries that are risk factors for coronary artery disease cannot provide sufficient oxygen to the starving heart, which then increases angina pain (chest pain) and the risk for heart disease (http://www.lifeheart.com).
A more scientific approach describes stress-induced heart disease as being controlled by a small molecule. One study claims that a small piece of RNA called miR-208 that occurs in the heart muscle controls damage to the heart under different types of stress. Mice were genetically engineered to not produce the RNA, and were compared to a control group. Both groups of mice were then exposed to conditions that exposed stress on their heart including hypothyroidism, heart enlargement and failure, and increasing how hard the heart had to pump. The study found that in the mice with normal miR-208 levels, heart damage occurred; the animals that were lacking the RNA had an overall healthier heart (http://www.sciencedaily.com).
What is the internet saying about how stress is harmful to the heart?
Long-term exposure to stress causes differing responses from your body; physical, cognitive, emotional, and behavioral signs are shown. When you don't give your mind and body a break from stress, you can worsen an existing health problem or develop a new illness. Some physical signs of stress include upset stomach, weight fluctuation, tiredness, a racing heart, insomnia, headaches, indigestion, and dizziness among others. Mental warning signs include worry, forgetfulness, a lack of creativity, an inability to make decisions, and a poor memory. Emotional signs include but are not limited to: anger, anxiety, depression, mood swings, irritability, loneliness, nervousness, and sadness. Behavioral signs include compulsive eating, bossiness, impulsive actions, alcohol/drug abuse, and withdrawal from social situations. Some ways to cope with stress include eating and drinking sensibly, reducing/stopping smoking, exercising, relaxing, taking responsibility, and getting rest (http://www.webmd.com).
According to some sources, it is not the stress itself but actually the individual that is the problem. People with Type A (impatient, competitive, extremely organized) personalities are at higher risk for developing coronary artery disease than Type B individuals. These two contrasting personalities will dictate how a person responds to a certain situation; whether with an adrenaline rush and a competitive response, or with a serene, calm response. Stressful situations in life are impossible to avoid completely, it is all about how the person will respond to the situation. A change in the way that stress is handled will actually help; some ways to do this include breathing exercises, yoga, meditation, and stretching exercises (http://heartdisease.about.com).
Often times, stress can be a result of work-related events. There is a high risk to physical and mental health for workers facing high psychological workload demands/pressures who have a lack of control concerning their career path. Specifically, approximately 23% of heart disease could be prevented if the level of job-related stress were reduced according to workhealth.org (http://www.workhealth.org/).
So how do we know all this stuff is true?
Essentially, we don't. There's actually no complete 100% foolproof "scientific evidence" to back up any of the above claims. But what we do know is that those people who do live in stressful environments are more likely to take up unhealthy habits like smoking, overeating, and not exercising. The Center for the Advancement of Health reports that although the connection between stress and heart disease varies widely among different people, the pattern is clearer among men (http://www.cfah.org/). They back up this claim by citing a study that says that chronic stress is linked to psychological distress, and a lack of coping skills and a bad support system can make the triggers even worse. Poor health habits cause metabolic changes in the body that can thus lead to cardiovascular disease. Evidence from a 30 month study of 152 married people with 80 taking care of spouses with Alzheimer's showed that the caregivers were at an increased risk for coronary heart disease as a result of the stress coupled with aging factors. The other 72 adults were a control group; the study began with tests for psychological stress levels and poor health habits, and the subjects were looked at for metabolic syndrome (high blood pressure, obesity, high cholesterol levels). The study showed that those who were caregivers in the beginning had a higher level of stress factors and suffered from ailments like obesity, a lack of sleep, and depression. In the beginning, heart disease was equally prevalent among both groups, and at the end of the study 54% of care-giving males suffered from heart disease versus 26% of the control group. Conclusively, the study found that stress factors lead to poor health habits, which contributes to cardiovascular disease. There was found to be a less clear pathway in women in which the connection between stress and heart disease remains unclear (Vitaliano et al., 1993).
Workhealth.org claimed that of 14 studies linking job strain to heart disease, 12 of those studies showed clear connections (while controlling other heart disease risk factors) (http://www.workhealth.org/). Webmd.com backed up their claims by citing a study that found high levels of posttraumatic stress disorder (PTSD) possibly raising men's heart risks after age 60 (http://www.webmd.com/). PTSD symptoms include flashbacks, hyper vigilance, frightening dreams, trouble sleeping, anger outbursts, and an inability to relate to others. The study included 1944 subjects, 1000 who took a PTSD survey in 1990 at an average age of 63, and 944 subjects who took the survey in 1986 at an average of 60. At the beginning, only 14 men were diagnosed with PTSD, but several men were also labeled medium-high risk. The subjects were followed for about 10-13 years, receiving checkups every 3-5 years, and 255 developed heart disease. The study found that the men with PTSD were more likely to develop heart-related problems, when taking smoking, blood pressure, cholesterol levels, and family history into account. The study did not look at other age levels or females (Kubzansky et al., 2007).
Why are people bothering with this information? Who cares?
Organizations like the American Psychological Association, the American Heart Association, and other online health journals have these articles as sources of information for the lay people. This information is meant to provide people with more knowledge about how stress can affect more than one aspect of their life. The Center for the Advancement of Health presented information and sources in order to educate people about the various risk factors that could affect their cardiovascular health.
So, what is the scientific community at large saying about the relation between stress and cardiovascular disease?
According to Bunker et al., some components of stress include depression, anxiety, panic disorder, social isolation or a lack of quality social support, acute and chronic life events, psychosocial work characteristics, and Type A behavior. Although depression, social isolation, or a lack of quality social support all were found to have a causal effect on coronary heart disease, there was no strong evidence to support the claim that chronic life events, work-related stressors, Type A Behavior Patterns, hostility, or anxiety disorders have a direct causal effect on coronary heart disease. Furthermore, the increased risk that does result is similar to how smoking and high blood pressure increase the risk for cardiovascular disease (Bunker et al., 2003). In other words, significant, acute stressors did not elicit a direct, negative cardiovascular response.
In another study, stress has shown to be found by endocrine abnormalities. In addition to a high waist-to-hip ratio, endocrine abnormalities can cause an extra accumulation of intra-abdominal, visceral fat as well as insulin resistance – both of which are high risk factors for cardiovascular disease, diabetes, and stroke. Depression, anxiety, alcohol consumption, and smoking are also direct effects of stress; all of which increase the risk of endocrine abnormalities. Metabolic syndrome often results, which directly stimulates cardiovascular disease (Björntorp, 1997). Furthermore, it has also shown that in times of great stress, the adrenal cortex responds with increased levels of hormone secretion. An excess of mineral corticoids secreted by the adrenal cortex induces cardiovascular disease through an elevation of blood pressure (Selye, 2004). These two studies tend to support the fact that stressors affect overall health, which in turn directly depresses cardiovascular health.
The British Medical Journal reports that when examining the association between self perceived psychological stress and cardiovascular disease, the prevalence and incidence of angina increased with increasing perceived stress. With decreased perceived stress, the prevalence of ischemia showed a weaker incidence. With higher stress incidence, there was also an increased chance to be admitted to the hospital for admission, but not necessarily for cardiovascular disease. The study found conclusively that the relation between high stress and angina was most likely due to the fact that people who reported high stress levels probably also tended to report symptoms more. Furthermore, it was found that the stress symptoms probably did not reflect increased incidence of any physical disease, and that any association between psychosocial measures and disease outcomes from other studies may not be completely accurate (Macleod et al., 2002).
One study which investigated the relationship between psychosocial work environment and cardiovascular heart disease found that with increased self-reported psychological job demands, the prevalence of heart disease increased as well. The study was completed by randomly selecting 13, 779 Swedish male and female workers. It was also found that workers without a social support system in the workplace also had a higher prevalence of heart disease; blue collar male workers had the strongest correlation between stressful situations at work and cardiovascular heart disease. The findings of this study actually suggest that there would be a difference in the findings depending on class and gender. However, the study does note that because of the design of the study, it is not completely possible to discern any causal relationship due to the fact that the temporal separation of work stress and heart disease is not possible (Johnson & Hall, 1988).
Interestingly, one review comments that one possible factor of cardiovascular health may be socioeconomic status (SES). Measures of SES include education, occupation, or income, and overtime evidence has accumulated that suggests a correlation between SES and mortality. Furthermore, studies have even shown that poor living conditions while growing up can actually lead to an increased risk to arteriosclerosis (Kaplan & Keil, 1993). From this information, it is easy to correlate how socioeconomic status can affect stress levels and psychological well-being.
Wrapping it up:
So, with all these differing opinions from researchers and other sources, what's the final conclusion? Does stress REALLY affect your heart's health? Should everyone start yoga classes in a frenzy? Not necessarily. From all the sources shown, it can be concluded that stress cannot be a decisive independent factor in cardiovascular disease. There is no direct, linear relationship. Stress actually influences other poor health habits, which in turn negatively affects heart health and coronary artery disease. So by maintaining stress to a minimum, people can positively affect other aspects of their health that will in turn keep their heart healthy.
Björntorp, P. (1997). Stress and Cardiovascular Disease. Acta Physiol Scand Suppl, 640, 144-148.
Bunker, S., Colquhoun, D., Esler, M., Hickie I., Hunt, D., Jelinek V., et al. (2003). "Stress" and Coronary Heart Disease: Psychosocial Risk Factors. Med J. Aust, 178, 272-276.
Johnson, J., & Hall, E. (1988). Job Strain, Work Place Social Support, and Cardiovascular Disease: A Cross-Sectional Study of a Random Sample of the Swedish Working Population. Am J Public Health, 78, 1336-1242.
Kaplan, G., & Keil, J. (1993). Socioeconomic Factors and Cardiovascular Disease: A Review of the Literature. Circulation by American Heart Association, 88, 1973-1998.
Kubzanksky, L., Koenen, K., Spiro III, A., Vokonas, P., & Sparrow, D. (2007). Prospective Study of Posttraumatic Stress Disorder Symptoms and Coronary Heart Disease in the Normative Aging Study. Archives of General Psychiatry, 64, 109-116.
Macleod, J., Smith, G., Heslop, P., Metcalfe, C., Carroll, D., & Hart, C. (2002). Psychological Stress and Cardiovascular Disease: Empirical Demonstration of Bias in a Perspective Observational Study of Scottish Men. British Medical Journal, 324, 1247.
Selye, H. (2004). The Evolution of the Stress Concept: Stress and Cardiovascular Disease. The American Journal of Cardiology, 26(3), 289-299.
Vitaliano, P., Russo, J., Bailey, S., Young, H., & McCann, B. (1993). Psychosocial Factors Associated with Cardiovascular Reactivity in Older Adults. Psychosomatic Medicine, 55, 164-177.
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