Pulse pressure is the difference between the top and bottom numbers of your blood pressure reading. A normal pulse pressure is about 40 mmHg. If that gap reaches 60 mmHg or more, it’s considered unusually wide and worth discussing with a healthcare provider, though the formal clinical threshold for a truly widened pulse pressure is above 100 mmHg.
How Pulse Pressure Is Calculated
Take your systolic (top) number and subtract your diastolic (bottom) number. If your blood pressure is 120/80, your pulse pressure is 40. If it’s 150/70, your pulse pressure is 80. The calculation itself is simple, but the number it produces tells you something important about how your heart and blood vessels are working together.
Pulse pressure reflects two things: how much blood your heart pushes out with each beat (stroke volume) and how flexible your large arteries are. When your heart contracts, blood surges into the aorta. If the aorta is elastic, it stretches to absorb that surge, keeping systolic pressure from climbing too high. A stiff aorta can’t absorb the impact as well, so systolic pressure rises while diastolic pressure may stay the same or drop. The gap widens.
What Counts as “Wide”
There’s no single cutoff where pulse pressure flips from safe to dangerous. A pulse pressure of 40 mmHg is considered average for a healthy adult. Once it climbs to 60 mmHg or above, most providers consider it worth monitoring. The formal clinical definition of a truly widened pulse pressure is anything over 100 mmHg. On the other end, a “narrow” pulse pressure is one that falls below 25% of your systolic reading.
Context matters. A pulse pressure of 55 in a 75-year-old is very different from the same number in a 30-year-old. The number should always be interpreted alongside your actual systolic and diastolic values, your age, and any other health conditions you have.
Why Pulse Pressure Widens With Age
Widening pulse pressure is, to some degree, a normal part of aging. Both systolic and diastolic blood pressure tend to rise together until about age 55. After that, they diverge: systolic pressure continues climbing while diastolic pressure starts to fall. This creates a progressively wider gap. The underlying reason is arterial stiffening. Over decades, the elastic fibers in your aorta and other large arteries lose flexibility, so they can no longer cushion each heartbeat as effectively.
This pattern is so common that isolated systolic hypertension (high top number with a normal or low bottom number) accounts for roughly 65% of hypertension diagnoses in elderly patients. Despite being the most common subtype of uncontrolled high blood pressure in people over 50, surveys show it’s underdiagnosed and undertreated in both older and younger adults.
Common Causes Beyond Aging
Aging arteries are the most frequent explanation, but several other conditions can widen pulse pressure, sometimes dramatically.
- Aortic valve regurgitation. When the aortic valve doesn’t close completely, blood leaks backward into the heart after each beat. This causes systolic pressure to rise (the heart pumps harder to compensate) while diastolic pressure drops (blood leaks back instead of maintaining pressure in the arteries). The result is a characteristically wide pulse pressure and a bounding pulse that rises and falls sharply.
- Hyperthyroidism. An overactive thyroid ramps up the cardiovascular system in multiple ways. Thyroid hormone dilates small arteries, dropping the resistance blood flows against. Heart rate can increase by 4 to 58 beats per minute, and cardiac output can rise by more than 1 liter per minute, reaching up to 300% higher than normal. All of this pushes systolic pressure up and widens pulse pressure.
- Severe anemia. When blood can’t carry enough oxygen, the heart compensates by pumping more volume with each beat. This increased cardiac output raises systolic pressure while diastolic may remain unchanged, widening the gap.
- Other high-output states. Conditions like Paget’s disease and severe thiamine deficiency (beriberi) share the same basic mechanism: the body demands more blood flow, cardiac output rises, and pulse pressure widens.
Why It Matters for Heart Health
A wide pulse pressure isn’t just a quirky number. It’s an independent predictor of cardiovascular problems. A large analysis of participants in cardiovascular outcome trials found that for every 10 mmHg increase in pulse pressure, the risk of death, stroke, or heart attack rose by 11%. That risk increase was consistent and statistically significant across the study population.
The reason is straightforward. A wider pulse pressure usually means stiffer arteries, and stiff arteries place extra strain on the heart with every beat. Over time, this contributes to left ventricular thickening, heart failure, and damage to smaller blood vessels in organs like the brain and kidneys. The pounding, high-pressure surges that come with each heartbeat in stiff arteries can also accelerate damage to blood vessel walls, promoting plaque buildup.
Getting an Accurate Reading
Pulse pressure is only as reliable as the blood pressure reading behind it. If your systolic number is artificially elevated by stress in a medical setting (sometimes called the white coat effect), your pulse pressure will look wider than it actually is day to day. Research in children and young adults has shown that the magnitude of the white coat effect directly correlates with 24-hour pulse pressure measurements and blood pressure variability, suggesting that people prone to this effect may also have some degree of arterial stiffness even if their usual readings are normal.
If your in-office pulse pressure seems high, home blood pressure monitoring or a 24-hour ambulatory monitor can give a more accurate picture. Take readings at the same time each day, sitting quietly for five minutes before measuring, with your arm supported at heart level.
How Wide Pulse Pressure Is Managed
Treatment depends entirely on the cause. If hyperthyroidism is driving the widening, treating the thyroid condition typically brings pulse pressure back to normal. If aortic regurgitation is responsible, the leaky valve itself needs to be addressed.
For the most common scenario, age-related arterial stiffness causing isolated systolic hypertension, blood pressure medications can help. A large retrospective analysis of veterans with hypertension found that a particular class of water pills was more successful at getting pulse pressure below 50 mmHg than five other medication classes tested. Your provider may also focus on lifestyle factors that influence arterial stiffness: regular aerobic exercise, reducing sodium intake, maintaining a healthy weight, and not smoking all help preserve arterial flexibility over time.
The goal isn’t necessarily to hit a specific pulse pressure number but to lower systolic blood pressure without pushing diastolic pressure dangerously low, which can be a real balancing act in older adults whose diastolic pressure is already on the lower side.