An Introduction to Blood Pressure BY UJVALA JUPALLI '25 Cover Image: Blood pressure should be checked more regularly as the one gets older. It is crucial to maintain a blood pressure of 120/80 mmHg by eating a wellbalanced diet and exercising daily. Image Source: Wikimedia Commons
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Overview and Trends of Blood Pressure Blood pressure is the force of one’s circulating blood against the walls of arteries and veins. Most of this pressure comes from the heart pumping blood through the circulatory system to the rest of the body. Blood pressure, also known as arterial pressure, is determined by the volume of blood ejected by the heart into the arteries, the elasticity of artery walls, and the rate of blood flow out of those arteries (Magder, 2018). There are two different types of blood pressure: systolic pressure and diastolic pressure. Systolic pressure is generated by cardiac contraction and is critical for pumping blood against gravity, up to the brain, and out to the rest of the body through arteries and capillaries. Diastolic pressure is the pressure in the arteries during cardiac relaxation that ensures continuous blood flow while the heart receives oxygen. According to the Center for Disease Control, a healthy and active adult should have a systolic blood pressure of less than 120 mmHg and a diastolic pressure of less than 80 mmHg. High blood pressure is a leading cause of cardiovascular disease, chronic kidney disease, dementia, and more. In 2015, high systolic blood pressure was associated with the death of over 8.5 million people (Zhou et al., 2021). However, problems with blood pressure are not spread
out evenly across low and high income regions. High blood pressure is more prevalent in lowerand middle- class countries rather than in highincome regions. This is evidenced by the decline of the mean systolic and diastolic blood pressures among high income regions and the increased mean blood pressure among women and men in East Asia, South Asia, and sub-Saharan Africa (Zhou et al., 2021). Determinants of Blood Pressure There are two main determinants of blood pressure. The strength of cardiac contraction determines systolic pressure since the pumping of the heart determines how much blood is in the arteries. Vessel resistance determines diastolic pressure as diastolic pressure depends on the speed of the blood flow back to the heart. This is also why blood pressure increases during physical exertion: the heart pumps stronger and faster to get more oxygen to the organs and muscles that are working. The volume of blood in the vascular space also plays a major role in determining blood pressure since more blood increases pressure (Magder, 2018). Environmental factors such as ambient temperature and altitude have also been shown to DARTMOUTH UNDERGRADUATE JOURNAL OF SCIENCE
