Low systolic blood pressure can cause dizziness, fatigue, and depression, among a number of other low blood pressure symptoms. These symptoms develop because the heart is unable to pump sufficient blood to the whole body, and some of the organs in the body may stop functioning normally because they don't get enough oxygen and nutrients. Treatment for low systolic blood pressure can include medications, changes to diet and exercise habits, and other measures, depending on the cause.
When a health care provider takes a blood pressure measurement, the reading includes two numbers for systolic and diastolic pressure. The first number should be higher, as it reflects the blood pressure when the heart actively beats to force blood into circulation. The second number will be lower, as it is taken when the heart is at rest. Low systolic blood pressure results in overall low systemic blood pressure, also known as hypotension.
Systolic blood pressure measurements below 90 can be indicators of low blood pressure, although some patients have naturally low measurements, especially athletes. A doctor will need to identify the symptoms of low systolic blood pressure to determine whether the patient actually has a medical issue. Poor circulation can contribute to dizziness, fainting, fatigue, and blurred vision. Some patients feel light headed and may develop extreme thirst or cognitive symptoms like depression.
In a case with severe low systolic blood pressure, kidney function may be impaired. When the kidneys do not get enough blood, they cannot filter it properly. Levels of some compounds may rise in the blood, and the patient can develop secondary symptoms. Other organs like the brain and liver may also struggle to function on less blood than usual. Patients may appear pale and clammy and could grow shaky and tired very easily, even with a simple activity like standing for several hours at an event.
Some patients develop an issue known as orthostatic hypertension, where changing position suddenly can cause a catastrophic drop in blood pressure. These patients have low systolic blood pressure until the body can normalize the pressure by contracting the blood vessels. Patients with this medical issue may experience normal blood pressure levels the rest of the time and could be capable of engaging in a wide variety of physical activities. A doctor can perform an evaluation, including asking the patient to lie or sit, wait, and then get up suddenly to watch for a drop in blood pressure related to positional changes.