Effects of high blood pressure on the blood vessels

Blood is pumped by the heart through "pipes" to every corner of the body. These pipes are called blood vessels. They are divided into arteries and veins. Arteries carry oxygen-rich blood from the heart to where its needed. They are more exposed to the pressure generated by the heart as a pump than the veins. Veins return the blood that has delivered nutrients and oxygen at its destination (so it is now low in oxygen) back to the heart.

Without a certain amount of pressure this circulation cannot work we need pressure to live.

Our blood vessels, both arteries and veins, have a similar structure. Both are made up of three layers:

The innermost layer ensures efficient exchange of nutrients and oxygen between the blood and the vessel wall. It consists of flat cells (the endothelium) and connective tissue.
The middle layer is made of smooth muscle cells and collagen and elastic fibers. It controls the vessels diameter by muscle contractions.
The outer layer is a network of elastic collagen fibers. It separates the vessel from the surrounding tissue, anchors it in place, and contains nerves and small vessels that supply it.

Arteries are structurally stronger and thicker than veins. Veins have thinner walls and can stretch more easily than arteries. Some veins have valves that prevent blood from flowing back into the limbs. This helps the blood return to the heart.
Blood pressure mainly affects the arteries. They can withstand the hearts pressure because especially the arteries near the heart can expand elastically and, during the hearts relaxation phase, compensate for the drop in pressure by contracting.

However, if a sustained high blood pressure presses on the arteries, they get damaged. Especially in the aorta, which is closest to the heart, bulges so-called aneurysms can form. In these cases the vessel wall can no longer withstand the pressure and forms expansions. Because the vessel wall at these spots no longer has its normal strength, the risk that the vessel will tear at that point is greatly increased.

There are different types of aneurysms: saccular, fusiform, dissecting (the vessel wall is split bleeding occurs between the wall layers) and pseudoaneurysm. In a pseudoaneurysm, a blunt or sharp injury causes a tear in the vessel wall. The surrounding tissue can contain the resulting hematoma and thus temporarily delay bleeding when a large artery is injured. However, this usually only works for a short time. Because this "aneurysm" forms outside the vessel wall, it is called falsum or spurium.

Small injuries can also form in the innermost layer of the arteries. Blood fats (for example cholesterol) and inflammatory cells can get stuck there and form so-called plaques. This is an ongoing process that gradually narrows the blood vessel and reduces blood flow. The vessel loses its elasticity and hardens (arteriosclerosis). It loses the ability to adapt to changing pressures, and blood pressure rises. Over time, plaques covered only by a thin endothelial layer can break through into the interior of the vessel. To repair this, platelets immediately deposit at that spot. This is similar to a skin wound where a scab forms to close it. The same now happens inside the vessel: platelets clump together and form a thrombus (blood clot). If the vessel is already severely narrowed by arteriosclerosis or the thrombus is large enough, it can completely block the vessel. It can also break off, get stuck at another narrowing, and block that vessel there.

As a result, the area supplied by the vessels downstream of the blockage no longer receives blood.
Depending on where in the body this happens, the blockage can lead to serious consequences such as a heart attack, stroke, kidney failure, and similar conditions.

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This article comes from BloodPressureDB – the leading app since 2011 that helps hundreds of thousands monitor their blood pressure every day. Our content is based on carefully researched, evidence-based data and is continuously updated (as of 11/2025).

Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care, and has led BloodPressureDB's specialist editorial team since 2015. Thanks to her extensive additional qualifications as a paramedic, first responder and in various therapy and emergency areas, she provides solid, practical and reliably reviewed information.

Effects of high blood pressure on the blood vessels

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