Blood pressure measures the force exerted by circulating blood against artery walls. The reading is given as two numbers, measured in millimeters of mercury (mm Hg). The first number, systolic pressure, represents the force when the heart beats and pumps blood. The second number, diastolic pressure, measures the pressure when the heart rests between beats. Understanding a reading of 105/65 mm Hg requires knowing the established categories for these measurements.
Decoding Blood Pressure Categories
The medical community uses specific ranges to classify blood pressure readings, which are derived from large population studies linking pressure levels to cardiovascular risk. A reading is considered “Normal” or “Optimal” when the systolic number is less than 120 mm Hg and the diastolic number is less than 80 mm Hg. Maintaining pressure within this range is associated with the lowest risk for heart disease and stroke.
Readings between 120–129 mm Hg systolic and less than 80 mm Hg diastolic are classified as “Elevated.” This level serves as a warning that a person is at risk of developing hypertension and should adopt lifestyle changes. Hypertension begins at “Stage 1,” defined as 130–139 mm Hg systolic or 80–89 mm Hg diastolic, which often warrants monitoring and sometimes medication.
Low blood pressure, or hypotension, is medically defined when a reading falls below 90 mm Hg systolic or below 60 mm Hg diastolic. These benchmarks help medical professionals determine a patient’s risk profile and guide interventions. The two numbers, systolic and diastolic, are equally important as they reflect different phases of the heart’s cycle.
How 105/65 Compares to Optimal Levels
A reading of 105/65 mm Hg places an individual firmly within the “Normal” or “Optimal” blood pressure category. Both the systolic pressure of 105 and the diastolic pressure of 65 are well below the established thresholds for elevated blood pressure and hypertension. This range is associated with a significantly reduced risk of pressure-related complications like heart attack or stroke.
Although 105/65 is numerically closer to the definition of low blood pressure (below 90/60 mm Hg), it is not considered clinically low unless it causes physical symptoms. Many healthy, active individuals, such as athletes, often have readings in this low-normal range, indicating efficient cardiovascular function. For a person with no symptoms, 105/65 is considered a favorable result.
This low-normal reading indicates that the heart does not need to work excessively hard to circulate blood throughout the body. The lower end of the normal range is often the goal for many therapeutic interventions aimed at reducing cardiovascular risk. In the absence of any concerning physical signs, 105/65 represents a healthy baseline.
When to Be Concerned About Low Readings
Blood pressure only becomes a medical concern when a low reading is accompanied by noticeable physical symptoms, known as symptomatic hypotension. These symptoms occur because the pressure is too low to adequately supply oxygen and nutrients to the brain and other vital organs. Common signs include feeling dizzy or lightheaded, especially when standing up quickly (orthostatic hypotension).
Other symptoms of insufficient blood flow include blurred vision, fatigue, nausea, and fainting. If a person consistently measures 105/65 but experiences none of these issues, the low-normal reading is likely normal for their body. However, a sudden, significant drop from a person’s typical baseline can cause symptoms and warrants attention, even if the reading remains above 90/60.
Temporary drops in blood pressure can be caused by factors like dehydration, certain medications, or standing for prolonged periods. If symptoms like persistent dizziness or recurrent fainting occur with a reading of 105/65, consult a healthcare provider. A medical professional can determine if the reading is a normal variation or a sign of an underlying issue, such as a heart or endocrine disorder.