Is it possible to be literally scared to death? Today, it’s commonly understood that mental stress and negative emotion can contribute to physical health problems including high blood pressure, heart disease, weight gain and more. However, this wasn’t always the case—our understanding of how physiological responses are tied to emotion remained poor until the 20th century. In fact, you may be surprised to hear that investigating the seemingly inexplicable phenomena of “voodoo” death helped lay the foundation for the study of the mind-body connection.
So, what is “voodoo” death and how could studying a type of black magic possibly have contributed to our scientific understanding of a crucial aspect of human physiology? In 1942, Walter B. Cannon, a Harvard physician and physiologist, began to hear reports of unexplained, sudden deaths within Indigenous communities from around the world. According to reports by anthropologists, natives who were cursed by others through “black magic” and bone pointing would inexplicably decline in health and pass away shortly thereafter. For example, in 1845 there was a case of a Maori woman who was told she would be killed by spirits because she ate fruit from a tabooed place; in less than 24 hours later, she was found dead.
Stories like these intrigued Cannon, who began to wonder what the rational explanation behind them could be. At first, he began to wonder if these natives had simply been poisoned, but urine tests and post-mortem examinations of “cursed” individuals revealed nothing out of the ordinary.
Instead, Cannon later found that these victims of “sorcery” experienced immense mental distress, becoming so convinced of their imminent demise that they would lay down in bed and refuse food and water as their bodies grew weaker. This distress and intense fear was worsened by the fact that friends and family of “cursed” individuals abandoned them, returning only to conduct sacred rituals that further implied their certain death.
Intriguingly, Cannon did observe one case in which a cursed victim had managed to survive: in North Queensland, a young man miraculously recovered almost instantly after the witch doctor who initially pointed a bone at him later told him that it was merely a joke. Similarly, if a cursed individual was blessed by a “medicine-man” through an elaborate ceremony involving a counter-charm, the victim would regain his strength and ask for water and food.
What could possibly account for these seemingly supernatural deaths? Cannon argued that a chronic, drawn-out state of mortal fear led to a physiological vicious cycle that eventually resulted in death.
The autonomic nervous system—which regulates involuntary bodily functions such as breathing, heart rate, and blood pressure—is split into two divisions: sympathetic and parasympathetic. These divisions play opposing roles; while the sympathetic nervous system prepares the body to respond to dangerous, stressful situations, the parasympathetic nervous system promotes “rest and digest.” As such, the sympathetic nervous system is often associated with the “fight or flight” response, which is a term Cannon himself coined in 1915.
Cannon therefore theorized that the chronic fear felt by “cursed” victims led to overactivation of their sympathetic nervous systems. This, he argued, stimulated the release of adrenaline from the adrenal medulla directly into the blood, leading to the constriction of small peripheral arteries. Cannon believed that this constriction resulted in an inadequate oxygen supply to the capillaries (the smallest blood vessels of the body), thus damaging them and allowing fluid to leak out of the blood circulation. This led to an overall reduction in blood volume, which was likely exacerbated by the dehydration and malnourishment experienced by curse victims. As a result, Cannon argued that cursed individuals experienced a “true state of shock”, in which a low blood pressure and lack of oxygenated blood damaged the muscle tissue of the heart. In turn, this weakened the very organ responsible for supplying the body with blood, thus leading to a vicious cycle.
Although Cannon lacked the tools and technology to thoroughly test this hypothesis, over 80 years later, modern science has built upon (rather than disproven) his theory. Advancements in endocrinology, neuroscience, molecular biology, immunology and more have filled in the gaps regarding the details of the complex physiological response to fear. For example, Cannon’s explanation did not include the effects of stress hormones such as cortisol, which are released by the adrenal cortex during sympathetic activation. However, this is because the chain reaction of hormones required to stimulate the release of cortisol was not fully understood until 1981 when Wylie Vale discovered the structure of Corticotropin Releasing Hormone (CRH). As such, Cannon could not have accounted for how brain regions responsible for fear and interactions between adrenaline and stress hormones work together to cause symptoms such as low blood pressure, cardiac arrhythmia (improper heartbeating) and loss of appetite.
Nonetheless, Cannon’s work made fundamental contributions towards understanding how emotion can influence physiological processes. Through the use of careful observation and logical thinking, Cannon was able to deduce a scientific and rational biological explanation for the seemingly magical phenomenon that was “voodoo” death. In doing so, he helped further our understanding of homeostasis (a term Cannon coined in 1926) and how the body maintains a dynamic balance in response to its environment.
So, remember to breathe, relax and take care of your body’s needs the next time you find yourself stressed out—there’s no stress, but the stress could be killing you!
_David Popa is a U3 student at McGill studying Anatomy and Cell Biology._
_Part of the OSS mandate is to foster science communication and critical thinking in our students and the public. We hope you enjoy these pieces from our_ [_Student Contributors_](https://www.mcgill.ca/oss/category/article-categories/student-contributors) _and welcome any feedback you may have!_