A widening pulse pressure means the gap between your systolic (top) and diastolic (bottom) blood pressure numbers is growing larger than normal. If your blood pressure reads 120/80, your pulse pressure is 40 mmHg, which is considered average. Once that gap reaches 50 mmHg or more, your risk of heart disease and stroke starts climbing, and a pulse pressure above 100 mmHg is considered truly widened.
This number doesn’t appear on most blood pressure monitors, but it’s easy to calculate yourself. And unlike systolic or diastolic pressure alone, pulse pressure reveals something specific about the health of your arteries and heart valves that neither number captures on its own.
How Pulse Pressure Works
Each time your heart contracts, it pushes a volume of blood into the aorta and large arteries. In healthy, elastic arteries, the vessel walls stretch to absorb that surge, then gently recoil between beats to keep blood flowing forward. This stretching and recoiling acts like a shock absorber: it keeps systolic pressure from spiking too high and diastolic pressure from dropping too low, holding the gap between them relatively narrow.
Pulse pressure is determined by two main factors: how much blood the heart ejects with each beat (stroke volume) and how easily the arteries stretch to accommodate it (arterial compliance). When stroke volume increases or arterial compliance decreases, systolic pressure rises while diastolic pressure stays the same or even drops. The result is a wider pulse pressure.
What Causes It to Widen
The most common reason for a widening pulse pressure is stiffening of the arteries, which happens gradually with age. Over decades, the elastic fibers in artery walls fracture and get replaced by stiffer collagen. Calcium and phosphorus deposits accumulate in the vessel walls, and proteins in the artery lining undergo a process called glycation, where sugar molecules permanently bond to them and create rigid cross-links. The cumulative effect is that arteries lose their ability to stretch. Systolic pressure climbs because the stiff vessels can’t absorb each pulse of blood, while diastolic pressure stays flat or drifts downward because the arteries no longer recoil effectively between beats.
Several specific conditions also widen pulse pressure:
- Aortic regurgitation. The aortic valve doesn’t close completely, so blood that was just pumped out leaks back into the heart during the resting phase. This drives systolic pressure up (because the heart compensates by pumping harder) and diastolic pressure down (because blood is flowing backward instead of maintaining forward pressure). The combination produces a noticeably wide gap.
- Hyperthyroidism. Excess thyroid hormone increases heart rate, strengthens heart contractions, and boosts cardiac output while simultaneously lowering resistance in the blood vessels. The net effect is higher systolic pressure with lower resistance in the periphery, widening the gap.
- Severe anemia. When iron deficiency becomes severe enough, the blood becomes thinner (less viscous), and the heart pumps harder and faster to deliver enough oxygen. This raises systolic pressure while diastolic pressure stays near normal.
- Aortic sclerosis. Thickening and calcification of the aortic valve, even without significant narrowing, can alter how blood flows out of the heart and contribute to a wider pulse pressure.
The Brain Pressure Connection
A suddenly widening pulse pressure can also signal a neurological emergency. When pressure inside the skull rises dangerously, as from a brain bleed, severe swelling, or a growing mass, the body triggers what’s known as the Cushing reflex. The brain detects that its own blood supply is being squeezed off by rising internal pressure, so it activates the sympathetic nervous system to force systemic blood pressure high enough to push blood through. Systolic pressure surges while diastolic pressure drops, producing a wide pulse pressure.
This reflex is part of a recognizable triad: widening pulse pressure, a slowing heart rate, and irregular breathing. If all three appear together, especially after a head injury or in someone with a known brain condition, it indicates that pressure inside the skull has reached a critical point. This is a late and ominous sign, not an early warning.
Why the Number Matters for Heart Risk
A widening pulse pressure isn’t just a marker of stiff arteries. It’s an independent predictor of cardiovascular events. Every 10 mmHg increase in pulse pressure raises the risk of coronary artery disease by roughly 23%. In a large study of primary care patients, those with elevated pulse pressure had a stroke rate of 5.5% compared to 3.4% in those without it, and heart failure rates of 5.0% versus 2.3%.
The reason goes beyond what the number reflects about artery health. A wider pulse pressure means the heart is working against greater resistance with each beat, increasing its workload over time. It also means that the organs receiving blood, particularly the brain, kidneys, and heart itself, are exposed to larger surges of pressure with every heartbeat. Over years, this pulsatile stress damages small blood vessels in those organs, accelerating the very conditions it predicts.
Getting an Accurate Reading
If you check your blood pressure at home or at a pharmacy and notice a pulse pressure of 60 mmHg or higher, it’s worth paying attention, but a single reading isn’t especially reliable. The stress of being in a medical setting (the “white coat” effect) tends to inflate systolic readings more than diastolic ones, which artificially widens the apparent pulse pressure. Research from hypertension specialists found that pulse pressure measured over a 24-hour monitoring period predicted cardiovascular problems significantly better than readings taken in a clinic.
The practical takeaway: look at trends, not individual readings. If your home blood pressure readings consistently show a gap of 60 mmHg or more, that pattern is more meaningful than any single measurement. Morning readings taken before coffee, before stress, and after sitting quietly for five minutes tend to be the most reliable.
How Aging Changes the Picture
In younger adults, high blood pressure typically shows up as elevations in both systolic and diastolic numbers. But after about age 50, a shift happens. Systolic pressure continues to rise while diastolic pressure plateaus or even declines. This divergence is almost entirely driven by arterial stiffening, and it’s why pulse pressure widens predictably with age.
This isn’t a benign quirk of getting older. The widening pulse pressure seen with aging is a direct reflection of how stiff the central arteries have become. Stiffer arteries also cause pressure waves to bounce back from branch points faster, arriving back at the heart while it’s still pumping rather than during the resting phase. This adds to the systolic peak and robs the diastolic phase of pressure, widening the gap further and forcing the heart to work harder with every contraction. Over time, this increased cardiac workload contributes to thickening of the heart muscle and, eventually, heart failure.
Factors that accelerate arterial stiffening, and therefore widen pulse pressure earlier in life, include diabetes (which increases the glycation cross-links that rigidify artery walls), chronic kidney disease, smoking, and long-standing high blood pressure itself. Regular aerobic exercise, on the other hand, is one of the few interventions consistently shown to improve arterial compliance and keep pulse pressure in a healthier range as you age.