04. Heart and circulation: how blood pressure, pulse and blood vessels are connected

KINGRAY ACADEMY · ARTICLE 04

Heart and circulation: how blood pressure, pulse and blood vessels are connected

How are the heart, blood, blood vessels and microcirculation connected?

Author: Ing. František Kokoš · Updated: 31 October 2026

The heart pumps blood, but blood vessels and the composition of blood also contribute to healthy circulation. This article explains the structure of the heart, pulmonary and systemic circulation, blood pressure and changes with age. It also explores links with cholesterol, blood sugar, movement and sleep, with an overview of related topics.

01 · How do the heart and circulation work?

The heart works continuously. Each contraction pushes blood into the vascular system.

The heart has four chambers: the right and left atria and the right and left ventricles. The atria receive blood and the ventricles pump it out. Valves help keep blood flowing in one direction. The heart’s electrical conduction system controls its regular contractions.

Pulmonary and systemic circulation

• Pulmonary circulation: the right ventricle sends blood through the pulmonary arteries to the lungs, where it takes up oxygen and releases carbon dioxide. The pulmonary veins carry it to the left atrium.
• Systemic circulation: the left ventricle pumps blood through the aorta to the body. After substances are exchanged in the tissues, blood returns through the veins to the right atrium.

Arteries carry blood away from the heart and veins carry it towards the heart. These names do not describe oxygen content: the pulmonary arteries carry less oxygenated blood and the pulmonary veins carry oxygenated blood. The coronary arteries supply the heart muscle itself.In simple terms: Arteries carry blood away from the heart and veins carry it back. Their names do not depend on how much oxygen the blood contains.

Heart structure and the path of blood: [1], [2].

Blood must pass through an extensive network of vessels:

Much of the exchange between blood and tissues takes place at the level of the smallest vessels.

02 · What is microcirculation?

Microcirculation is blood flow through the network of the smallest vessels: arterioles, capillaries and venules. An artery branches into smaller vessels, blood passes through a dense capillary network and returns to the veins through venules.

Capillaries have very thin walls. Oxygen, nutrients, carbon dioxide and other substances are exchanged between blood and tissues across these walls. Some capillaries are so narrow that red blood cells pass through them one at a time.In simple terms: Capillaries are exchange points: tissues receive oxygen and nutrients and release substances that need to be carried away.

03 · Blood pressure: why one number is not enough

Blood pressure is the pressure of blood against artery walls. It is recorded as two values in mmHg. Systolic pressure is the higher value when the heart pumps blood out. Diastolic pressure is the lower value between contractions, when the heart relaxes and fills with blood.

In a reading of 120/80 mmHg, 120 is the systolic pressure and 80 is the diastolic pressure. This illustrates how a reading is written; it is not an individual treatment target. Blood pressure and pulse are different measurements: pulse describes the number of beats per minute.In simple terms: Blood pressure involves two numbers. Pulse is different — it tells us how many times the heart beats per minute.

The cardiac cycle and both pressure values: [3].

Blood pressure naturally changes throughout the day. Movement, stress, sleep, caffeine, alcohol, hydration and other circumstances can influence it.

A single random measurement may therefore not describe the true situation. When monitoring blood pressure at home, use the correct technique and comparable conditions.

Guidelines on assessing blood pressure: [7].

Symptoms of high and low blood pressure

High blood pressure often causes no symptoms. Headaches, palpitations or ringing in the ears cannot confirm or rule it out on their own. Proper measurements and professional assessment are what matter. [13]

Low blood pressure generally means a reading below 90/60 mmHg. Some people have no symptoms; dizziness, weakness, blurred vision or fainting are particularly important. Symptoms after standing up may reflect a postural drop in blood pressure. Recurring problems need medical assessment. [14]

04 · Blood vessels are more than passive tubes

The inner surface of blood vessels is lined by the endothelium. It is an active tissue involved in many processes.

Nitric oxide (NO) is an important signalling molecule involved in regulating vascular tone.In simple terms: The lining of blood vessels helps control their widening and narrowing. Nitric oxide is one of the signals involved.

05 · Blood is not water: its properties matter too

Circulation is often discussed mainly in terms of the heart and blood vessels. Blood itself and its physical properties are also important.In simple terms: The same everyday expression can refer to different problems. First, we need to establish which one is involved.

Several factors can influence the way blood flows through vessels.

06 · Blood clotting is essential to life

The ability of blood to form a clot is a natural protective mechanism. Without it, even a small injury could be a serious problem.

However, excessive clot formation or a clot forming in an inappropriate location can lead to thrombosis.

The body continuously maintains a complex balance between clot formation and mechanisms that limit it or later break the clot down.In simple terms: The body needs to stop bleeding after an injury while also preventing clots from forming inappropriately inside blood vessels.

07 · Cholesterol is more than one number

Cholesterol is a natural component of the body. Cardiovascular risk is more complex than simply dividing cholesterol into “good” and “bad”.

Atherosclerosis is a process in which plaque forms in an artery wall. It is different from a blood clot, although damage to a plaque can trigger clot formation.In simple terms: Plaque is a change in an artery wall. A clot forms from blood. They are different, although a damaged plaque can trigger clot formation.

Assessment of lipids and overall risk: [8].

08 · Blood sugar, insulin and blood vessels

The heart and blood vessels are closely connected to metabolic health. Persistently elevated blood glucose and diabetes are important factors in vascular damage.

Caring for circulation therefore involves more than tracking blood pressure or cholesterol. A broader view of metabolic health matters.In simple terms: One good number is not enough. Blood pressure, blood fats and blood sugar need to be considered alongside everyday habits.

09 · Movement is a foundation of healthy circulation

Movement changes the oxygen and blood flow requirements of muscles and other tissues.

Regular physical activity supports cardiovascular fitness and offers many other health benefits. You do not have to start with running or extreme training.

Start with activity you can do regularly and increase the effort gradually. If you have known heart disease, new symptoms or a long period of inactivity, discuss the appropriate intensity with a doctor.

10 · Muscles help blood return through the veins

Blood must return from the lower limbs towards the heart. Muscle activity helps this process.

During walking, the muscles of the lower limbs contract regularly and help move blood through the veins towards the heart. This mechanism is often called the muscle pump or calf muscle pump.In simple terms: Muscle contractions during walking help return blood from the legs to the heart. This is one reason to break up long periods of sitting.

11 · Smoking: a major risk factor you can change

Smoking is an essential consideration in heart and vascular health. It damages the vascular system and substantially increases cardiovascular risk.

For someone who smokes, stopping smoking can be a much more significant step than searching for another supplement “for the blood vessels”.

Modifiable risk factors and prevention: [6], [9].

12 · Sleep and stress also affect the heart

Cardiovascular health also extends beyond diet, cholesterol and movement.

Long-term stress and poor sleep can be related to the autonomic nervous system, blood pressure, metabolism and everyday behaviour.In simple terms: Sleep and stress are also connected with how the body regulates pulse and blood pressure and with our daily habits.

13 · What is HRV, and what can it tell us?

HRV, or heart rate variability, describes changes in the time intervals between individual heartbeats.In simple terms: HRV measures small differences in the time between heartbeats. It is not the number of beats per minute, and one reading alone does not determine health.

A healthy heart does not work like a perfectly regular metronome. Heart rhythm naturally adapts to breathing, movement, sleep, stress and autonomic nervous system activity.

Many factors influence HRV. Following your own trend under similar conditions can be more useful than comparing a single result with another person’s result.

14 · Blood pressure, ECG and other tests

Each method answers a different question. Results need to be assessed in the context of the device used, measurement conditions, symptoms and health status.

• Blood pressure measurement: shows pressure in the arteries at the time of measurement. Home monitoring requires a validated monitor, an appropriately sized cuff and correct technique.
• ECG: records the heart’s electrical activity and helps assess its rhythm. It does not measure whether all blood vessels are open.
• Echocardiography: uses ultrasound to show the structure of the heart, its valves and its pumping function.
• Laboratory tests: for example, a complete blood count, lipid profile or blood glucose test provide additional information about individual risk factors.

Watches and other devices can track pulse or HRV; some also have medical functions. Their capabilities depend on the particular device and its intended use. An indicative reading or a normal result from one measurement does not rule out every disease.In simple terms: Every measurement has capabilities and limits. A normal smartwatch reading does not rule out every heart or blood vessel problem.

ECG and ultrasound of the heart: [5].

15 · Light and photobiomodulation: what do they mean?

Photobiomodulation (PBM) uses light of particular wavelengths to produce photobiological reactions in tissues.

This is a broad research field. Each application must be assessed according to the method, wavelength, light dose and specific aim.In simple terms: A result from one light-based procedure cannot automatically be applied to another device. The specific settings and purpose matter.

The heart and blood vessels with advancing age

With age, large arteries may become less elastic and the heart may respond differently to exertion. The valves and the heart’s ability to relax between contractions may also change. The extent of these changes varies between people.

Atherosclerosis is not an inevitable part of normal ageing. Age increases risk, but blood pressure, blood lipids, diabetes, smoking, physical activity and family history also matter. New breathlessness, chest pain or a marked decline in exercise capacity should not automatically be attributed to age.In simple terms: Age is one risk factor, but not the only one. New symptoms should not simply be dismissed as part of getting older.

Care therefore includes regular activity suited to your abilities, a varied diet, not smoking, sleep and monitoring risk factors during preventive check-ups. If you already have heart or vascular disease, a doctor will tailor your treatment and routine to your condition.

Changes in the heart and blood vessels with age: [4].

❤️ What should you take away from this article?

The cardiovascular system is a connected network in which the heart and other components cooperate.

It is also influenced by:

❤️ Caring for the heart means caring for the whole circulation

The heart, blood, blood vessels, microcirculation, movement, metabolic health, sleep and stress are connected. It makes sense to view cardiovascular health as one interconnected system.

📚 Scientific sources