Differences between Diastolic and Systolic
Contents
Diastolic vs. Systolic Pressure
A blood pressure reading records two measurements that correspond to the different phases of the cardiac cycle: systolic and diastolic pressure.[1][2] These figures indicate the force of blood against the artery walls.[3] Blood pressure is measured in millimeters of mercury (mmHg).[3] A reading is given as the systolic number over the diastolic number.[4][5]
Systolic pressure, the top number in a reading, measures the pressure in the arteries when the heart contracts to pump blood to the rest of the body. Diastolic pressure, the bottom number, is the pressure in the arteries when the heart is at rest between beats. During diastole, the heart chambers fill with blood.
Both numbers in a blood pressure reading provide important information about cardiovascular health. Elevated systolic pressure is a major risk factor for cardiovascular events, particularly in older adults. High diastolic pressure also increases the risk of heart disease and stroke.
Blood pressure is measured with a device called a sphygmomanometer, which includes an inflatable cuff that is wrapped around the upper arm. The cuff is inflated to temporarily restrict blood flow, and then the pressure is slowly released.[3]
Comparison Table
| Category | Systolic Pressure | Diastolic Pressure |
|---|---|---|
| Phase of Heartbeat | Contraction (heart pumping blood) | Relaxation (heart filling with blood) |
| What is Measured | Maximum pressure in arteries during a heartbeat[4][5] | Minimum pressure in arteries between heartbeats[4][5] |
| Position in Reading | Top number | Bottom number |
| Normal Range (Adults) | Less than 120 mmHg | Less than 80 mmHg |
| Elevated | 120–129 mmHg | Less than 80 mmHg |
| Stage 1 Hypertension | 130–139 mmHg | 80–89 mmHg |
| Stage 2 Hypertension | 140 mmHg or higher | 90 mmHg or higher |
| Hypertensive Crisis | Higher than 180 mmHg | Higher than 120 mmHg |
Clinical Significance
Hypertension, or high blood pressure, is diagnosed when readings are consistently 140/90 mmHg or higher. It often has no symptoms but increases the risk for serious health problems like heart attack, stroke, and kidney failure.
Isolated systolic hypertension is a condition where the systolic pressure is high (140 mmHg or more) but the diastolic pressure remains normal (less than 90 mmHg). This is the most common form of high blood pressure, particularly in older individuals, and is linked to a higher risk of stroke and heart disease.
Isolated diastolic hypertension occurs when the diastolic pressure is 80 mmHg or higher while the systolic pressure is in the normal range (less than 130 mmHg). This condition is more common in younger adults. While its immediate risks may be less severe, it can increase the future risk of cardiovascular problems.
Treatment for high blood pressure often involves lifestyle modifications such as a healthier diet, regular physical activity, and reducing salt intake. In many cases, medication is also prescribed to control blood pressure.
References
- ↑ "medicalnewstoday.com". Retrieved February 01, 2026.
- ↑ "wikipedia.org". Retrieved February 01, 2026.
- ↑ 3.0 3.1 3.2 "healthdirect.gov.au". Retrieved February 01, 2026.
- ↑ 4.0 4.1 4.2 "nih.gov". Retrieved February 01, 2026.
- ↑ 5.0 5.1 5.2 "nevadacardiology.com". Retrieved February 01, 2026.
