Measuring Blood Pressure

Correct cuff position for measuring blood pressure

A normal Heart Sound with no audible murmurs:

Korotkoff Sounds

Auscultatory blood pressure measurement showing onset of Korotkoff sounds at systolic pressure, and diminishing sounds as diastolic pressure is reached:

Blood pressure sounds with slowly deflating cuff. Notice that slower deflation provides for more beats and potentially increased accuracy for onset of systole or detection of diastolic end-point.

Classification of Blood Pressure for Adults Age 18 and Older*

Category Systolic (mmHg) Diastolic (mmHg)
Normal † <120 and <80
Prehypertension 120–139 or 80–89
Hypertension ‡
Stage 1 140–159 or 90–99
Stage 2 >160 or >100
* Not taking antihypertensive drugs and not acutely ill. When systolic and diastolic blood pressures fall into different categories, the higher category should be selected to classify the individual’s blood pressure status. For example, 140/82 mmHg should be classified as stage 1 hypertension, and 154/102 mmHg should be classified as stage 2 hypertension. In addition to classifying stages of hypertension on the basis of average blood pressure levels, clinicians should specify presence or absence of target organ disease and additional risk factors. This specificity is important for risk classification and treatment.

Normal blood pressure with respect to cardiovascular risk is below 120/80 mmHg. However, unusually low readings should be evaluated for clinical significance.

Based on the average of two or more readings taken at each of two or more visits after an initial screening.
*Source: ACE Personal Trainer Manual

Although fitness professionals cannot diagnose hypertension, they can play an active role in measuring their clients' blood pressure. This can be a useful practice especially if a client's physician has recommended regular blood pressure monitoring before, during, and/or after exercise. Furthermore, middle-aged and older-adult clients who have neglected visiting their physicians for periods longer than 12 months should have their blood pressure measured prior to starting an exercise program to determine if it is safe for them to exercise. Since hypertension is a cardiovascular risk factor, if a client presents with abnormally high blood pressure readings, it could be an indication that the client should be referred to his or her physician before becoming more physically active.

Blood pressure reflects the force of the heartbeat and the resistance of the arteries to the pumping action of the heart. It is measured in millimeters of mercury (mmHg). The larger number represents systolic blood pressure, which is the pressure created by the heart as it pumps blood to the body. This is the maximum pressure created by the heart during a complete cardiac cycle. The smaller number represents diastolic blood pressure, which is the pressure that remains in the arteries during the filling phase of the cardiac cycle, when the heart relaxes. It is the minimum pressure within the arteries during a complete cardiac cycle.

Measuring Blood Pressure

Blood pressure is measured using a sphygmomanometer and stethoscope after a client has been seated with both feet flat on the floor for two full minutes. The cuff should fit firmly around the arm with its lower margin about one inch above the antecubital space. It is important to use an appropriate-sized cuff as very obese clients may have falsely elevated blood pressure readings with small, standard-sized cuffs. The arm should be comfortably supported on either an armchair, or by the trainer, at an angle of 10 to 45 degrees.

Place the stethoscope over the brachial artery using a minimal amount of pressure so as not to distort the artery. The stethoscope should not touch the cuff or tubing. Rapidly inflate the cuff to 20 to 30 mmHg above the point when the pulse can no longer be felt at the wrist. Release the pressure at a rate of about 2 mmHg per second, listening for sounds. The systolic pressure is determined by the first perception of sound. The diastolic pressure is determined when the sounds cease to be heard or when they become muffled. (Listen to the example on the right)

If a blood pressure reading needs to be repeated due to errors during the first attempt, allow 30 to 60 seconds between trials so normal circulation can return. A duplicate measurement should be performed on the other arm. Record each of the results for comparison with subsequent measurements. If abnormal readings result, repeat the measurement on the opposite (first) arm again. If there is a significant discrepancy between readings from arm to arm, it could represent a circulatory problem, and the client should be referred to a physician for a medical evaluation.