Hypertension: The Silent Killer

David M. Wheeler

University of Alaska Fairbanks

August 1, 2024

Hypertension is an extremely prevalent disease around the world. It is often paired with comorbidities, like diabetes or obesity, and often leads to secondary issues. Often referred to as the silent killer because of the effects it has on various parts of the body, many consider the disease to be mostly preventable.  The purpose of this paper to familiarize and go further in depth on the cardiovascular system objective 42: explain the structure and function of the heart, discuss health impacts of hypertension, and compare treatment options.

The human heart is broken down into two halves with four separate chambers. The right half of the heart is responsible for receiving deoxygenated blood by way of the superior and inferior vena cava into the right atrium. The right atrium passes the blood to the right ventricle before sending it to the lungs for oxygenation through the pulmonary artery.  Oxygenated blood is then returned to the heart through the pulmonary vein, reaching the left atrium, then the left ventricle. The oxygenated blood is then sent by the left ventricle through the aorta to the tissues to exchange oxygen and carbon dioxide. Due to force need to pump large volumes of blood, the left side of the heart is larger and myocardium is thicker than the right side.

There are several contributing risk factors to hypertension including sedentary life style, diet, sodium intake, obesity, stress levels, and sleep habits.  These are all controllable factors than can lead to hypertension. On the other hand, genetics is a risk factor that isn’t controllable. If left untreated, severe hypertension could lead to congestive heart failure, cerebral hemorrhage, and renal failure. Those with treated hypertension still have a higher risk and occurrence of myocardial infarction and thrombotic stroke (Doyle, 1991). Hypertension is often associated with physiological changes to the heart and vessels. In a study conducted by Yilmaz and Ozkan (2021), they found that participants with unexplained left ventricular hypertrophy, defined as increased wall thickness of the left ventricle, have a high prevalence of masked and undiagnosed hypertension. Relating this back to the baseline structure of the heart, the left ventricle is larger the right, but hypertension unhealthily increases the left ventricular wall’s thickness. This means that more pressure and force is required to eject blood from the left ventricle as well as less space within the ventricle for blood to fill.  Yildez et al (2020) confirmed this by stating the left ventricle is a primary target for hypertensive end-organ damage. Left ventricular hypertrophy is known to lead to abnormal heart rhythms like atrial fibrillation and ventricular arrhythmias, which are all risk factors for sudden cardiac death (Shenasa 2017). Hypertension impacts organs beyond the heart. The long-term stress high blood pressure puts on arteries causes abnormal wall viscosity creating artery stiffening due to influence of hypertension on the arteries smooth muscle (Simon et al, 2001).

There are three approaches to treating hypertension: anti-hypertensive medications, lifestyle changes, or a combination of anti-hypertensive medications and lifestyle changes. “There is a dearth of research directly comparing the effects of treatment through medication and physical activity, which has made it difficult to assess which intervention yields the best outcome for hypertensive patients. (Noone et al., 2018). Standard treatment for hypertension is prescribed medication that you will likely take the rest of your life without lifestyle change. Personally, I have been borderline hypertensive since high school. My entire life I have been an athlete, occasionally falling out of shape due to injuries, but generally a very active and overall healthy person. With medication, I have slight changes in blood pressure (~10 mmHG systolic and diastolic) keeping my blood pressure around 130/80. Being a lifetime athlete and now Soldier, I am very active, with no change in my blood pressure based on diet and exercise. In comparison, last year my brother was diagnosed with hypertension. My brother is significantly more sedentary than I and has a higher body mass index. He took the alternative treatment option, increased his exercise and chose healthy foods. At his 6-month follow-up, he effectively decreased his blood pressure within healthier boundaries, now similar to mine around 130/90. These examples support the combination approach of treatment. I imagine my blood pressure would be significantly higher without my active lifestyle and medication. Without our genetic predisposition, I imagine that our hypertension would be preventable with just the exercise and lifestyle change. The mechanisms behind why physical fitness may reduce blood pressure is still unclear, but many believe that is could be due to changes in insulin sensitivity, autonomic nervous system function, and vasoconstriction regulation (Noone et al., 2018).

Hypertension is a silent killer due to minimal symptoms associated with. You could live a lifetime unknowingly having moderate hypertension. It is a silent killer because, over time, it can remodel and harm the health of your heart and arteries, and overall give you an increased risk of sudden cardiovascular death or devastating neurologic events. Screenings for hypertension assist with preventing or improving physiological changes to your body by decreasing your blood pressure with medications and lifestyle changes.

References:

Doyle A. E. (1991). Hypertension and vascular disease. American journal of hypertension, 4(2 Pt 2), 103S–106S. https://doi.org/10.1093/ajh/4.2.103s

Noone, C., Dwyer, C. P., Murphy, J., Newell, J., & Molloy, G. J. (2018). Comparative effectiveness of physical activity interventions and anti-hypertensive pharmacological interventions in reducing blood pressure in people with hypertension: protocol for a systematic review and network meta-analysis. Systematic reviews, 7(1), 128. https://doi.org/10.1186/s13643-018-0791-9

Shenasa, M., & Shenasa, H. (2017). Hypertension, left ventricular hypertrophy, and sudden cardiac death. International journal of cardiology, 237, 60–63. https://doi.org/10.1016/j.ijcard.2017.03.002

Simon, A., & Levenson, J. (2001). Effect of hypertension on viscoelasticity of large arteries in humans. Current hypertension reports, 3(1), 74–79. https://doi.org/10.1007/s11906-001-0084-9

Yildiz, M., Oktay, A. A., Stewart, M. H., Milani, R. V., Ventura, H. O., & Lavie, C. J. (2020). Left ventricular hypertrophy and hypertension. Progress in cardiovascular diseases, 63(1), 10–21. https://doi.org/10.1016/j.pcad.2019.11.009

Yılmaz, Ö. Ç., & Özkan, S. (2021). Is Masked Hypertension an underlying Cause of Unexplained Left Ventricle Hypertrophy?. Clinical and experimental hypertension (New York, N.Y. : 1993), 43(2), 138–141. https://doi.org/10.1080/10641963.2020.1825729