Chapter 5: Blood Pressure

What are Blood Pressure Ranges?

Blood pressure is reported in mm Hg (pronounced millimetres of mercury), in which the systolic is the numerator and diastolic is the denominator. See Table 5.1 for an overview of estimated blood pressure ranges for healthy individuals.

Table 5.1: Estimated Blood Pressure Ranges (mm Hg)

Age Systolic Range Diastolic Range
Newborn to 6 months 45–90 30–65
6 months to 2 years 80–100 40–70
Children (2–13 years) 80–120 40–80
Adolescent (14–18 years) 90–120 50–80
Adult (19–40 years) 95–135 60–80
Adult (41–60 years) 110–145 70–90
Older adult (61 and older) 95–145 70–90

Points to Consider

The average blood pressure for an adult is sometimes noted as 120/80 mm Hg. However, this is only an average and the healthcare provider needs to consider acceptable ranges for individual clients. For example, in adults, normal blood pressure can range from 95–145/60–90 mm Hg. The healthcare provider considers the client’s baseline blood pressure and the client’s current health state in conjunction with subjective data and other objective data. For example, a blood pressure of 90/50 mm Hg may be normal for a healthy, asymptomatic 20-year-old adult.

Factors that influence blood pressure include age, sex, ethnicity, weight, exercise, emotions/stress, pregnancy, and diurnal rhythm as well as medication use and disease processes.

  • The general pattern is that blood pressure rises with age, so normal variations tend to be higher for older adults.
  • Blood pressure is similar in childhood for males and females. After puberty, females have lower blood pressure than males, whereas after menopause females have higher blood pressure than males.
  • Research has revealed that ethnicity may be a predictor of blood pressure, but this causation is not necessarily biological, but rather sociocultural. When determining risk for high blood pressure, it is important to consider ethnicity as a contributing factor.
  • The diurnal cycle influences blood pressure to be lower in the morning and increase throughout the day until early evening. Try it out: take your blood pressure when you wake up in the morning and then again in late afternoon, and note the difference. This is one reason why healthcare providers document the time a client’s blood pressure is taken.
  • Blood pressure can be higher in people who are obese because the heart has to work harder to perfuse the body’s tissues.
  • The sympathetic nervous system is stimulated by exercise, stress, anxiety, pain, anger, and fear, which increases blood pressure. Blood pressure returns to baseline within five minutes of rest following activity. Try it out. Have a peer take your blood pressure. Then, run on the spot or do some other cardiac activity for five minutes. Have the peer take your blood pressure again, and then lie down and rest for five minutes. Take the blood pressure again. Note the changes.
  • Blood pressure varies throughout the duration of pregnancy. It decreases about halfway through the first trimester until mid-pregnancy due to progesterone effects that relax the walls of blood vessels, causing decreased peripheral vascular resistance. It returns to pre-pregnancy values toward the end of pregnancy.

Points to Consider

White coat syndrome refers to elevated blood pressure due to nervousness or anxiety when clients have their blood pressure taken by a healthcare provider. This occurs in approximately 20% of clients. Key message: have the client take their blood pressure at home with an automatic home blood pressure cuff and compare the findings. Alternatively, you can ask the client to sit quietly and leave the room while an automatic cuff takes a client’s blood pressure. The automatic cuff can be programmed to take three measurements and the blood pressure documented is an average of the three readings.