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Getting to the Heart of Circulation

The anatomy of healthy blood flow


Getting to the Heart of Circulation

The circulatory system is a closed loop that starts and ends with the heart. While that sounds simple enough, it’s actually a highly intricate network composed of approximately 60,000 miles of blood vessels.


The purpose of circulation

The body’s muscles, tissues, and organs require a continuous replenishment of oxygen, nutrients, and hormones to maintain their physiologic functions. These materials are packaged in the blood and pumped by the heart to the target tissues via blood vessels.

Once these goods are delivered to the muscles, tissues, and organs, the blood collects waste products, such as carbon dioxide, to be eliminated from the body.

When all goes well in the circulatory system, our muscles, tissues, and organs can function properly. But any chink in the circulatory chain can negatively impact the healthy functioning of our organs and cause diverse signs and symptoms as a result.



Arteries are strong, muscular blood vessels which carry oxygen-rich blood away from the heart (except for the pulmonary arteries, which carry oxygen-poor blood from the heart to the lungs). Arteries can withstand a great amount of pressure generated by blood flow from the heart.

Capillaries are tiny, thin-walled blood vessels responsible for the delivery of oxygen, nutrients, and hormones to the tissues, as well as the collection of carbon dioxide and waste products.

Veins are vessels responsible for returning deoxygenated blood to the heart. Veins operate with a system of valves to ensure blood moves in one direction.


Live circuit

Imagine the blood vessel network as a tree. A tree’s trunk branches off into a couple large branches, which continue to divide into smaller, more numerous twigs.

In a similar way, the left side of the heart pumps oxygen-rich blood through the aorta, which then branches off into large arteries going to different places in the body. Arteries divide into smaller arterioles as they get closer to their destination, and then end in tiny capillaries which perfuse the target tissues with blood.

Capillaries have thin walls, which allows for the delivery of oxygen, nutrients, and hormones from the blood to the tissues, as well as the collection of carbon dioxide and waste products.

The capillaries also begin the process of returning oxygen-poor blood to the heart. Capillaries merge into venules, which eventually converge to form larger veins. Veins deliver deoxygenated blood to the heart.

The right side of the heart then pumps this blood to the lungs to release carbon dioxide and reoxygenate the blood via respiration. The pulmonary veins return oxygenated blood to the heart so that the circuit can begin again.


The heart of the matter

The heart is the key player in the circulatory system. This hollow, muscular organ is responsible for maintaining strong, rhythmic contractions that pump blood into the arteries and maintain blood pressure.

A healthy circulatory system depends upon the proper functioning of the heart itself, comprising its electrical conduction, valve system, as well as its own blood perfusion. (A bit of a chicken-and-egg phenomenon: a healthy heart also depends on healthy circulation!)

Electrical impulses in the heart set the rate and rhythm of heartbeats in the left and right atria (upper chambers) and ventricles (lower chambers).

Valves control the flow of blood between the atria and ventricles, and form dividers between the heart and the arteries.

Coronary arteries perfuse the heart itself by delivering oxygen-rich blood to all three layers of the heart’s muscle wall.

Problems may arise if the heart’s electrical signalling becomes dysregulated (e.g., arrhythmia), its valves become leaky and allow for backward blood flow (e.g., valvular insufficiency), or if the heart muscles are poorly perfused with blood (e.g., coronary artery disease).


Poor circulation

Circulation is compromised if there is an obstacle to delivering blood to the tissues. This obstacle might arise anywhere in the circulatory system (e.g., plaque in the coronary artery, embolism in the lungs, valve dysfunction in the veins).

Although the extremities are commonly affected, poor circulation can present with myriad signs and symptoms all over the body. The symptom presentation depends on the tissues being affected by the lack of oxygen.

Bear in mind that poor circulation isn’t a disease in itself but a result of an underlying condition. Share your concerns with your healthcare provider so that you receive a thorough assessment and appropriate treatment.


Body systems work together


Nervous system

During rest, the nervous system slows heart rate; during stress, it tells the heart to speed up.


Endocrine system

Hormones can constrict and dilate the blood vessels, which changes blood pressure. Heart rate can also be altered by thyroid hormone.


Lymphatic system

This system collects plasma (the liquid part of blood) that has been pushed out of the capillaries and returns it to the bloodstream to maintain healthy fluid balance.


Circulation-supporting supplements


improves serum lipid levels and may reduce risk of cardiovascular disease


extract is cardioprotective and may be helpful for hypertension, coronary artery disease, and peripheral arterial disease

Chinese patent medicines

remedies used to move blood stasis have been shown to help patients with cerebral infarction

ginkgo biloba

extract has antioxidant and platelet-inhibiting effects which may benefit cardiovascular disease, peripheral vascular disease, and diabetic vascular complications

butcher’s broom

extract may improve edema from chronic venous insufficiency


extract possesses serum lipid-lowering, antioxidative, and cardiovascular protective properties

gotu kola extract with Pycnogenol

taken together reduce progression of subclinical arterial plaques and reduce oxidative stress


supplementation has been shown to lower blood pressure to an effect comparable to diet and exercise interventions

Korean red ginseng

supplementation has been shown to lower diastolic blood pressure in prehypertensive patients


Symptoms of poor circulation

-          cold extremities

-          numbness

-          tingling

-          muscular weakness or pain while walking

-          pale or blue skin

-          swelling

-          bulging veins


Common causes of poor circulation

-          diabetes

-          obesity

-          smoking

-          hypertension

-          atherosclerosis

-          peripheral artery disease

-          varicose veins

-          Raynaud’s disease

-          deep vein thrombosis


Healthy circulation practices

-          wear compression stockings

-          elevate feet and legs

-          exercise

-          eat a healthy diet

-          don’t smoke

-          try far-infrared therapy

-          dry brush regularly


This article was originally published in the February 2024 issue of alive magazine.



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Matthew Kadey, MSc, RDMatthew Kadey, MSc, RD