Blood Pressure (With Detailed)
Blood pressure is the pressure exerted by Wood on the wall of a blood vessel.
Blood pressure may also be defined as the arterial blood pressure, which is the force exerted by circulating blood on the walls of systemic arteries.
Systolic blood pressure: This is the maximum pressure exerted by blood on the walls of blood vessels which develops at the peak of ventricular systole. Systolic blood pressure = 120 mm Hg
Diastolic blood pressure: This is the minimum pressure exerted by blood on the wall of blood vessels during ventricular diastole. Diastolic blood pressure = 80 mm Hg
Measurement of blood pressure
Blood pressure is measured clinically with a sphygmo-manometer which is either of mercury or aneroid type.
Advise the patient to rest at least 15-20 minutes. The patient should be in a sitting or lying position. There are two methods for taking blood pressure:
- Palpatory method
- Auscultatory method
Physiological variations of blood pressure
Diurnal variation
Blood pressure is lowest early in the morning and highest in the afternoon.
Also read: Blood | Types, Composition, Functions & More
Age
Blood pressure rises with age. The systolic blood pressure at different ages:
Infancy = 80-90 mm Hg
Childhood = 90-110 mm Hg
Adult = 110-120 mm Hg
Elderly = 140-150 mm Hg
Sex
Before the occurrence of menopause in females, both the systolic and diastolic blood pressures are slightly lower than males. After menopause blood pressure may be slightly higher than males of the same age.
Also Read: Male and Female Reproductive System
Body build
Obese persons tend to have higher blood pressure.
Sleep
In resting conditions as in sleep, blood pressure is decreased.
Exercise
Light exercise such as walking increases the systolic blood pressure but decreases the diastolic blood pressure.
In severe exercise, the systolic blood pressure may rise up to 180 mm Hg.
Posture
Standing causes an increase in both systolic and diastolic blood pressure.
Excitement or Emotion
This may cause an increase in systolic blood pressure.
After digestion of blood
There is a slight rise in systolic blood pressure, but the diastolic blood pressure falls due to vasodilation in certain vessels of the body.
Regulation or control of Blood pressure
The following factors affect and regulate blood pressure. As we know:
Blood pressure= Cardiac output x Peripheral resistance.
Cardiac output = stroke volume x heart rate.
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Blood pressure category Systolic mm Hg (upper #) Diastolic mm Hg (lower #)
Normal less than 120 less than 80
Prehypertension 120-139 80-90
High Blood Pressure 140-159 90-99
(Hypertension) Stage 1
High Blood Pressure 160 or higher 100 or higher
(Hypertension) Stage 2
