How The Cardiovascular System Works

A run-down on the cardiovascular system: 

• The cardiovascular system is made up of the heart, blood vessels and blood, working together to transport oxygen, nutrients and other essential substances throughout the body.
• The primary function of the cardiovascular system is to deliver oxygen and nutrients to cells, remove waste products, and help maintain the body's internal balance, including temperature regulation.
• Blood circulates through two connected pathways: the pulmonary circulation, which carries blood to and from the lungs, and the systemic circulation, which delivers oxygen-rich blood throughout the body.
• Cardiovascular health can be supported through everyday habits such as regular physical activity, a balanced diet, adequate sleep, stress management and avoiding smoking.

Every second of every day, your cardiovascular system is working to keep blood moving through your body. It transports oxygen and nutrients to your cells and carries waste products away. 

It helps to picture the cardiovascular system as a tree. The ‘trunk’ is the body’s main artery. Then, there’s the aorta, which branches into larger arteries and then smaller and smaller vessels until they form a fine network of capillaries. Blood travels out from the heart, through the arteries, and returns through the veins, looping continuously to help keep your body functioning1.

This guide explores what the cardiovascular system is, what it does, the organs involved, and how you can support cardiovascular health through everyday habits. 

What is the cardiovascular system?

The cardiovascular system is made up of three key components: the heart, a complex network of blood vessels (arteries and veins), and the blood itself. The system plays an essential role in your overall health, with every other system in your body depending on the blood it circulates 2.

Its core job is transport. It delivers oxygen and nutrients to all your cells, carries hormones and other vital substances where they're needed, and collects waste for removal. Arteries carry blood away from the heart, while veins return it arteries1. 

Your cardiovascular system is working constantly to keep the environment around each cell just right for that cell to function, which is exactly why healthy circulation matters so much3 4 .

Why the cardiovascular system is important

Every organ and tissue in your body relies on a steady blood supply. From your brain to your muscles, cells depend on the oxygen and nutrients delivered through the bloodstream. Supporting your cardiovascular health can help support the function of the body’s wider systems3 4.

What does the cardiovascular system do?

It's easy to think of circulation as just "pumping blood around," but the cardiovascular system function goes beyond that. It has at least three important roles: 

• Transporting nutrients and oxygen into tissues while removing waste products and carbon dioxide5.
• Carrying hormones, cytokines and immune cells5.
• Helping maintain homeostasis, which is the body's stable internal balance of things like temperature and pH5.

Body temperature regulation is one example of the many functions the cardiovascular system performs. As blood circulates through the body, it also transports heat generated by tissues, helping move warmth from the body's core to the skin, where it can be released.⁴ 

How does the cardiovascular system work?

Low-oxygen blood is pumped from the heart's right ventricle into the pulmonary artery, which branches into smaller arteries and capillaries that wrap around tiny air sacs in your lungs. Here, carbon dioxide moves out of the blood to be exhaled, while oxygen moves into the bloodstream. 

This oxygen-rich blood then returns to the left side of the heart through the pulmonary veins, where it is pumped out to the rest of the body. The process repeats continuously and forms an essential part of the function of the cardiovascular system¹.

Cardiovascular system organs explained

The cardiovascular system isn't a set of isolated parts. It's one connected network, where each component depends on the others to keep blood moving. Here's a look at the main organs in the cardiovascular system and how they fit together. 

The heart

The heart is the muscular pump at the centre of it all, pushing blood directly into the arteries, either the aorta or the pulmonary artery6. It has four chambers, which work together to support two connected pathways: the left side supplies the systemic circulation (the body loop), and the right side supplies the pulmonary circulation (the lung loop)7.

Blood vessels

Blood vessels form the network through which blood travels. There are three main types:

• Arteries carry blood away from the heart. Larger arteries are thick and elastic to accommodate higher pressure, while smaller arteries (arterioles) help regulate blood flow to different tissues⁶.
• Capillaries are the smallest blood vessels. Their thin walls allow oxygen, nutrients and waste products to be exchanged between the blood and surrounding tissues⁶.
• Veins return blood to the heart and contain valves that help prevent blood from flowing backwards⁶.

Blood

Blood is the fluid that circulates throughout the cardiovascular system. As it travels through the arteries, veins and capillaries, it transports oxygen, nutrients, hormones and immune cells to tissues throughout the body. It also helps carry carbon dioxide and other waste products away from cells so they can be removed⁷ ⁸.

Factors that can influence cardiovascular health

Cardiovascular health is influenced by a range of factors, many of which are linked to everyday lifestyle habits. Habits like eating a balanced diet, being physically active, maintaining a healthy weight, avoiding tobacco use, getting adequate sleep and managing stress can help support cardiovascular health⁹.

On the flipside, there are a few habits that may play a role in how chronic conditions, including cardiovascular ones, develop over time. These include smoking, excess alcohol intake, ongoing stress, poor dietary patterns, physical inactivity and inadequate sleep. Social connection and overall wellbeing may also play a role in long-term health outcomes¹⁰.

Everyday habits that support cardiovascular health

Supporting cardiovascular health is often about the habits you maintain consistently over time. Lifestyle changes have a real, measurable impact on cardiovascular health11, so here are a few worth weaving in:

• Stay active consistently. Regular movement is one of the most reliably supported habits for cardiovascular health and can help support healthy circulation11.
• Manage your stress. Ongoing stress can influence heart health, so finding what helps you unwind matters more than you may think10.
• Prioritise sleep. Quality, adequate sleep supports cardiovascular health as well as your overall wellbeing9 11.
• Stay hydrated. It's easily overlooked, but adequate hydration supports normal cardiovascular function and overall health¹² . 
• Eat a varied diet. Diets rich in fruits, vegetables, legumes, wholegrains and healthy protein sources are associated with better cardiovascular outcomes.¹³˒¹⁴ Limiting highly processed foods, trans fats and sugary drinks may also support a happy heart. 
• Limit smoking and excess alcohol. Easing back on both is consistently linked with better cardiovascular outcomes10 11.

If you have concerns about your cardiovascular health, speak with your healthcare professional for personalised advice and support.

Looking to learn more? Explore the Swisse Wellness Hub for articles about acts of wellness and what a health–focused routine looks like. 

References:

1. Institute for Quality and Efficiency in Health Care. (2023). How does the blood circulatory system work? [online] National Library of Medicine. Available at: https://www.ncbi.nlm.nih.gov/books/NBK279250/
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3. King, J., & Lowery, D. R. (2023). Physiology, cardiac output. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK470455/
4. Pittman, R. N. (2011). The circulatory system and oxygen transport. In Regulation of tissue oxygenation [Internet]. Morgan & Claypool Life Sciences. https://www.ncbi.nlm.nih.gov/books/NBK54112/
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9. Arnett, D. K., Blumenthal, R. S., Albert, M. A., et al. (2022). Lifestyle factors for cardiovascular health. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC9750923
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11. Ghodeshwar, G. K., Dube, A., & Khobragade, D. (2023). Impact of lifestyle modifications on cardiovascular health: A narrative review. Cureus, 15(7), e42616. https://doi.org/10.7759/cureus.42616
12. Watso, J. C., & Farquhar, W. B. (2019). Hydration status and cardiovascular function. Nutrients, 11(8), 1866. https://doi.org/10.3390/nu11081866
13. Diab, A., Dastmalchi, L. N., Gulati, M., & Michos, E. D. (2023). A heart-healthy diet for cardiovascular disease prevention: Where are we now? Vascular Health and Risk Management, 19, 237–253. https://doi.org/10.2147/VHRM.S379874
14. Lichtenstein, A. H., Appel, L. J., Vadiveloo, M., et al. (2021). 2021 dietary guidance to improve cardiovascular health: A scientific statement from the American Heart Association. Circulation, 144(23), e472–e487. https://doi.org/10.1161/CIR.0000000000001031