Many of us know or have heard that stress, particularly chronic stress, is unhealthy. Not just that it may have psychological or emotional consequences, but that it has adverse effects on us physically as well. Despite having this vague sense that stress has negative effects on our health, I didn’t really understand the physical mechanisms through which stress could impact our bodies until recently reading an excerpt from “Why Zebras Don’t Get Ulcers” (Sapolsky 1994). In this book, Sapolsky explains how chronic stress can lead to cardiovascular disease (CVD)—the leading cause of death in the United States. He describes how typically, when we get stressed, our heart rate and blood pressure increase, arteries dilate, and we experience increased blood flow to our muscles and decreased flow to nonessentials such as digestion. While these responses would be adaptive in “fight-or-flight” circumstances, chronic activation of such a response essentially wears down our cardiovascular system, causing hypertension, an imbalanced heart, an inflammatory response in our blood vessels, and increased likelihood that atherosclerotic plaque will stick to these inflamed areas, causing heart attacks or stroke.
I think there are two main difficulties associated with tackling the issue of chronic stress leading to CVD. First, it is largely invisible to us. We may feel our heart racing when we are stressed, but we cannot actually see the effects it may be having on our cardiovascular system without medical equipment. Relatedly, it is a long-term problem and therefore the damage may not be visible until years into living a stressed-out lifestyle. When we are weighing the pros and cons of completing a grant proposal or essential work presentation on time, we probably are not considering that the stress may be contributing to future cardiovascular issues.
Perhaps identifying more specific concepts or behaviors than general “stress” would help us to monitor our behavior better to help combat CVD in the future, and scientists are attempting to make these links. For example, Newman et al. (1995) found that participants who displayed any amount of hostility in an observational interview had a greater risk of incident ischemic heart disease (IHD) than those who displayed no hostility. This may suggest that working to decrease hostile thoughts or behavior may decrease our risk of heart disease. Unfortunately, there were several limitations to this study. For example, Whooley & Wong (2011) called into question Newman et al.’s (1995) results due to the fact there were very few patients who actually demonstrated no hostility (about 10%), making it difficult to draw firm conclusions based on the data, and the mechanism linking hostility to IHD was also unexplored. Therefore, it is difficult to say whether reducing hostility may actually improve cardiovascular outcomes.
Tuck, Adams, Pressman, & Consedine (2016) explored another characteristic that may help explain differences in CVD that I refer to as the “fake-it-till-you-make-it” trait. That is, they found that a participant’s ability to express positive emotion was associated with lower CVD risk scores. Perhaps the ability to appear happy or unstressed actually lowers stress levels and leads to a lower risk of cardiac problems. While Tuck at al. (2016) did find significant results, their experiment was highly questionable. Firstly, their sample was biased—it was largely White and female, and additionally was self-selecting. Secondly, when split into gender groups, their results were only significant for men. Thirdly, while they found a significant relationship between ability to express positive emotions and CVD risk scores, they were unable to accurately assess whether this may also be true of the ability to express negative emotions because of facial coding problems and an uneven distribution of results. If, when properly examined, ability to express negative emotions was also related to CVD risk scores, we may infer very different conclusions about why there may be a connection to CVD risk scores. Finally, the researchers were unable to establish the direction of the relationship. That is, while it is possible that the ability to express positive emotion buffers men from CVD, it is also possible that men with generally poorer health are less able to signal positive emotions.
I believe that much of the difficulties associated with conducting the types of studies I discussed above arise from the long-term nature of behaviors that may lead to CVD as well as the huge multitude of behavioral, environmental, and genetic contributions that may lead to increased risk of CVD. In many cases, CVD may present itself at the center of a perfect storm between individual and environmental factors. However, working to understand what the greatest risk factors are and how to effectively communicate these risks to the public to produce real behavioral change is the challenge we are faced with as we attempt to combat this deadly disease. In addition, if the experiments described above are even somewhat on the right track, it seems that emotion regulation that involves decreasing stress and increasing positive and calming affect may be important to our cardiac health. I am excited to explore such techniques in future posts!
Newman, J. D., Davidson, K. W., Shaffer, J. A., Schwartz, J. E., Chaplin, W., Kirkland, S., & Shimbo, D. (2011). Observed hostility and the risk of incident ischemic heart disease: a prospective population study from the 1995 Canadian Nova Scotia Health Survey. Journal of the American College of Cardiology, 58(12), 1222-1228.
Sapolsky, R. M. (1994). Why zebras don’t get ulcers. New York: WH Freeman.
Tuck, N. L., Adams, K. S., Pressman, S. D., & Consedine, N. S. (2017). Greater ability to express positive emotion is associated with lower projected cardiovascular disease risk. Journal of Behavioral Medicine, 1-9.
Whooley, M. A., & Wong, J. (2011). Hostility and cardiovascular disease.