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The Cardiovascular System: An Overview

Here's an overview of the cardiovascular system, its functions and some terms that you may need to refresh your knowledge of..

Cardiovascular system key terms


As with many of the bodies systems the cardiovascular system has many terms that you may not be familiar with but will hear time and time again.  To help you understand these new terms we have listed them in the following table.  Please note that you may need to read through all the cardiovascular system pages here at for these terms and definitions to make complete sense!




Refers to the heart, blood and blood vessels


Means to maintain a constant internal body temperature


Receptor of the nervous system that detects changes in temperature


Is when a blood vessel narrows, making it harder for blood to flow through it


Is when a blood vessel widens, making it easier for blood to flow through it


Receptor of the nervous system that detects how dilute the blood is


Low body fluid levels


Excessively high body fluid levels


This refers to the constant regulation of the body's internal environment to maintain a stable living condition

What is the cardiovascular system?Personal training cardiovascular system


The cardiovascular (CV) system is made up of the heart, the blood and the vessels through which blood travels, as seen in the adjacent image. 

What does the cardiovascular system do?


The CV system works in combination with the respiriatory system to maintain homeostasis. 

The heart acts as a mechanical pump which provides the force to move the blood through the blood vessels to the tissues and organs of the body.

This allows the CV system to help maintain homeostasis by enabling it to carryout its four major functions.

The four major functions of the CV system are:

1.   Transportation of nutrients, gases and waste products

2.   Protection from infection and blood loss

3.   Maintenance of constant body temperature (‘thermoregulation’)

4.   Maintaining fluid balance within the body

Why is the CV system important?

personal training gas exchange

The CV system is essential for sustaining life and it’s therefore important to ensure that it is kept in good health.

This is because the CV system is the workhorse of the body, continuously functioning to push blood to the tissues and the organs that need it. 

Failure of the CV system to do this can have serious consequences.  Two common examples of the CV system failing are a heart attack or a stroke, which can both leave the person in very ill health and often result in death.

It is therefore vital when working in the fitness industry that you have a sound knowledge and understanding of this important system, its structure and function.  As this will help you keep it healthy and safe by recognising when it is over stressed and when it can be pushed harder.

The cardiovascular system and fitness


As opposed to skeletal muscle, the heart is comprised of cardiac muscle and the blood vessels are comprised of smooth muscle. 

personal training cardiac muscleExercise and fitness benefit cardiac and smooth muscle in the same way as it benefits skeletal muscle.  So as we exercise and improve our fitness we are also strengthening and improving the health of the heart and blood vessels, two of the key components of the CV system.

Fitness can be seen as how well your body is conditioned to deal with the demands you place upon it and your heart is essentially the engine that drives your body, as it constantly pumps oxygenated blood and nutrients to the tissues and organs that need it.

By improving the health and condition of the heart and blood vessels, the CV system is better equipped to efficiently deal with the daily stresses placed on it and cope with exercise on a more regular basis.

personal training climbing stairsSo when working in the fitness industry and especially as a personal trainer, it is your responsibility to assess CV fitness, establish client goals and ensure you keep them safe. 

One of the key ways of doing this is by designing tailored and specific cardiovascular and resistance exercise programmes that can improve the health and function of your clients cardiovascular system.

For example, a client prior to training with you may have struggled walking up 5 flights of stairs at work and playing more than 15 minutes of touch rugby on a Thursday night.  However if you were to give them the right type of training they can improve their cardiovascular fitness and therefore their ability to complete these tasks and activities.

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