Blood pressure measures the force of blood pushing against the walls of your arteries as it circulates through the body. Monitoring this force provides important information about how hard the heart is working and the overall health of your circulatory system. A blood pressure reading is a fundamental metric used by healthcare providers to assess a person’s risk for various health conditions. Understanding what these numbers signify, and where a reading of 108 falls, is a step toward better health awareness.
Decoding the Blood Pressure Reading
Every blood pressure measurement consists of two distinct numbers presented as a fraction, such as 120/80 mmHg. The unit “mmHg” stands for millimeters of mercury, the standard way blood pressure is recorded. These two numbers correspond to different phases of the heart’s cycle. The top number, known as the systolic pressure, indicates the force exerted on artery walls when the heart contracts and pumps blood out. The lower number, the diastolic pressure, measures the force when the heart relaxes and refills with blood between beats.
Understanding Blood Pressure Ranges
Standard guidelines classify blood pressure into several categories. A reading is considered normal if the systolic pressure is less than 120 mmHg and the diastolic pressure is less than 80 mmHg. Readings between 120–129 systolic and less than 80 diastolic are categorized as elevated, suggesting a need for lifestyle modification. A systolic reading of 108 mmHg falls firmly within the normal range for most adults and is often described as low-normal.
This low-normal reading is generally a favorable health indicator, as the goal is to reduce strain on the heart while ensuring proper blood flow. The official threshold for clinically defined hypotension is typically below 90 mmHg systolic or 60 mmHg diastolic. Therefore, a reading of 108 is comfortably above the level where healthcare providers would formally diagnose low blood pressure.
When Low Blood Pressure Becomes a Concern
True hypotension is defined by a reading below 90/60 mmHg, but more importantly, by the presence of symptoms. A low-normal reading like 108/70 is only considered problematic if it leads to noticeable physical signs. For some people, a low reading is simply their normal, healthy baseline.
When blood pressure drops significantly, organs, particularly the brain, may not receive enough blood flow. This lack of adequate perfusion causes symptoms associated with symptomatic hypotension. These signs include dizziness or lightheadedness, especially upon standing, general fatigue, blurred vision, nausea, and fainting (syncope).
Causes of Symptomatic Hypotension
Symptomatic low blood pressure often results from underlying issues affecting blood volume or heart function. Dehydration is a common cause, as reduced fluid volume directly lowers blood pressure. Certain medications, including those for hypertension, heart conditions, or depression, can also lower blood pressure too much. Other causes include sudden blood loss, severe infection (sepsis), or endocrine problems such as an underactive thyroid.
When to Seek Medical Attention
If a person experiences a sudden, significant drop in pressure accompanied by severe symptoms like confusion, rapid and shallow breathing, or cold, clammy skin, immediate emergency medical attention is necessary. For less severe but persistent symptoms like chronic lightheadedness, consult a healthcare provider to investigate the root cause, even if the reading remains above the 90/60 mmHg threshold.