What Are Normal Fluctuations in Blood Pressure?

Normal blood pressure fluctuates by 30 to 40 mmHg (millimeters of mercury) in reaction to emotional or physical stress. According to the National Blood, Heart, and Lung Institute, people who are diagnosed as hypertensive have wider fluctuations, with differences of 60 to 80 mmHg.

Measurement

• Blood pressure readings are recorded with two numbers, for example 120/80, and correspond to the pumping action of the heart. When the chambers of the heart contract, it is called systole (top number). When they relax, it is called diastole (bottom number).

Significance

• According to Ann Belanger, R.N., author of "Vascular Anatomy and Physiology," causes of increased fluctuation and high blood pressure are excessive salt intake, poor kidney function and high levels of stress hormones, such as cortisol and angiotensin, that contribute to fluid imbalance.

Other Factors

• The strength of the heartbeat, elasticity of the artery wall and resistance of the capillaries (small blood vessels) also influence blood pressure. Stiff, or sclerosed, arteries cannot flex in response to pressure. Smoking and fatty deposits can damage and harden arteries.

Effects

• Over time, high blood pressure causes abnormally expanded arteries (aneurysms) to form while other arteries narrow. Heart muscle and kidneys weaken. Blood clots may block circulation in the heart or brain, resulting in heart attack or stroke.

Risks/Solution

• According to the National Heart, Lung and Blood Institute, every increment of 20/10 mmHg above normal (120/80), raises a person's risk of developing cardiovascular disease. A blood pressure of 140/90 or higher requires intervention. Lowering blood pressure by healthy diet and exercise decreases arterial plaque and improves the chances of avoiding heart attack or stroke.