Systolic blood pressure is the first number heard with a stethoscope or displayed on a digital blood pressure machine when a blood pressure reading is being performed. It is the top number of a blood pressure reading. If your blood pressure is 130 over 70, displayed as 130/70 on your medical chart, 130 is the systolic blood pressure reading. The top number or systolic blood pressure reading reflects the amount of pressure exerted against the blood vessels when the heart contracts–the systolic phase of the cardiac cycle that includes contraction then relaxation.
If systolic blood pressure or diastolic blood pressure remains too high, damage to the heart, arteries and kidneys can occur. Harmful changes that occur to the heart, arteries and kidneys happen over time. Symptoms may not be present. Each time the heart beats or contracts, it sends oxygen containing blood to the organs of the body. If systolic blood pressure is low, dizziness, rapid heart rate and fainting can occur. Low systolic blood pressure can cause increased heart rate in an attempt to nourish the brain the kidneys. States of shock, caused by low systolic blood pressure (hypotension), can lead to kidney failure and brain damage from death of the cells if not corrected.
Systolic blood pressure increases with age. Your reading should be less than 140 to reduce risk of stroke, heart attack and kidney damage. Readings over 140 cause the arteries to stiffen. They become less elastic and more prone to blockages leading to heart disease and kidney failure. Systolic blood pressure less than 90 is considered too low, though without symptoms. In people with existing heart disease, it may be considered normal.
To determine if systolic blood pressure is too high or too low, several readings may need to be performed. It is normal for blood pressure to vary throughout the day and in response to medications taken, hydration, activity and stress.
Systolic blood pressure may be too high or too low. If it is low, the condition is known as hypotension. If it is too high, it is known as systolic hypertension.
High systolic blood pressure can be controlled but not cured. Medications and lifestyle changes, such as limiting salt intake, exercise, weight loss, stress reduction and pain control can help keep systolic blood pressure from remaining too high. In cases of low systolic blood pressure, medications may be needed that help the kidneys hold onto salt. Some individuals experience low blood pressure from a condition known as neurally mediated hypotension. Adequate hydration is important to keep blood pressure from becoming too low. Discovery of the cause of low blood pressure is necessary to target the treatment needed.
Controlling systolic blood pressure may be as important as maintaining lower diastolic blood pressure (less than 90) to maintain good health. Past studies have shown that systolic blood pressure readings over 140 can contribute to overall mortality. A very recent study, published in the Cochrane Review, shows there is not enough evidence to suggest the importance of controlling systolic blood pressure lower than 140 with medications to reduce deaths from heart disease and stroke. Studies are ongoing to discover the best treatment for high systolic blood pressure.
Understanding that systolic blood pressure can put stress on the heart seems to indicate that keeping your blood pressure--both the top (systolic), and lower (diastolic) numbers within normal range. Maintain a healthy weight, know what your salt intake should be for your overall health status, exercise and maintain fluid balance to keep your systolic blood pressure normal.