Blood Pressure | UC Davis Sports Medicine | UCDavis Health

What is blood pressure

Blood pressure is a measure of the force blood exudes on the arterial wall during the heart’s contraction or pumping phase (know as systole) and relaxation phase (known as diastole). Systolic pressure is the higher of the two values. Blood pressure relates to circulation of blood through the arteries and the arterial resistance to blood flow.

Pressure is usually measured noninvasively with a sphygmomanometer. In this manner, a cuff around the upper arm is inflated to a pressure higher than arterial pressure in order to stop blood flow through the brachial artery in the arm. As the cuff pressure is slowly released, blood begins to flow again through the artery and is associated with a thumping sound. By listening through a stethoscope, the first thumping sound of blood flowing through the artery is recorded as systolic pressure. Once the flow is completely restored, the thumping sounds disappear and at the final muffling sounds are recorded as diastolic pressure.

Pressure readings are presented as systolic/diastolic and values up to 120/80 mmHg (millimeters of Mercury) are considered normal. Readings from 120/80 to 139/89 are considered pre-hypertensive, and readings of 140/90 and higher are considered hypertensive. The diagnosis of hypertension is not based on an isolated elevated reading. It is made when two separate and independent readings yield values ≥140/90. As yet, there are no defined “lower limits” of blood pressure.

What factors affect blood pressure?

Systolic pressure is affected by a variety of factors. Factors such as anxiety, caffeine consumption, and performing resistance and cardiovascular exercises, cause immediate, temporary increases in systolic pressure. During cardiovascular exercise, for example, systolic pressure can increase to values close to and over 200 with higher levels of effort. Diastolic pressure, on the other hand, is a relatively stable value during exercise and under daily activity. It does not fluctuate significantly throughout the day, or in response to outside influences. During cardiovascular exercise, this value may even decrease. Long-term factors that may lead to hypertension include smoking, hardening of the arteries (called Arteriosclerosis), having excess body weight, eating large amounts of salt, taking certain medications, and being exposed to chronic stress.

People who have high blood pressure are at increased risk for cardiovascular disease which includes stroke and heart failure, kidney disease, and all-cause mortality. High blood pressure means that the cardiovascular system has to work much harder in order to circulate blood throughout the body. For people who are mildly hypertensive, with readings around 140/90, the most effective means of controlling blood pressure is lifestyle modification. Regular cardiovascular exercise, eating a low-salt, low-fat diet, and maintaining a healthy body weight are ways that one can optimize blood pressure values. Blood pressure values are actually reduced for up to three hours after completing a cardiovascular exercise session!   For individuals with more severe hypertension well above 140/90, medication may be prescribed. There are several types of medications that can be taken. For example, beta-blockers act to reduce the heart’s need for oxygen by decreasing resting heart rate and the heart’s contractility. Calcium channel blockers act to dilate blood vessels, thus decreasing peripheral resistance.

The effect of high blood pressure (hypertension) has several well-established negative health implications. These include but are not limited to, Atherosclerosis and heart disease. Atherosclerosis is the build-up of cholesterol on the walls of arteries, which may eventually result in the blocking of blood flow. When this occurs in the arteries of the heart, it is called coronary artery disease and can result in a heart attack.

From a performance stand point, hypertension is more of a health concern. Systolic blood pressure can reach dangerous levels and American College of Sports Medicine (ACSM) guidelines recommend to consider stopping exercise when blood pressure reaches 250/115 and/or a 10 mm Hg drop in systolic blood pressure with increased workload occurs.