What is Cardiovascular Fitness?

What your heart and veins can do for you!


By Maddy Bond


Cardiovascular fitness. You hear these words around all the time, but what exactly is it, and why does it even matter? Strictly speaking, cardiovascular fitness refers to an individual's VO2 max and how efficiently the body utilizes oxygen. Measuring an individual’s VO2 max requires special equipment and tests, and the range can vary based on gender and age.

The numbers listed on the chart below refer to the amount of oxygen utilized in milliliters, per kilogram of body weight per person, ranging from average to excellent. Anyone can condition themselves to raise their aerobic capacity, however there is a genetic barrier. You’d usually see a higher VO2 max in professional athletes. For example, male Olympic cross country skiers have been known to have a VO2 max of 70 ml/kg/min!

Check out the formula in our previous blog post to find out yours, and use the chart above to see where you fit on the scale. That’s all well and good, but why does our VO2 max matter? What does the cardiovascular system actually do?

The cardiovascular system refers to the huge and crucial network of the heart, arteries, veins, and capillaries in our bodies. It’s so big that if all of a person’s veins and arteries were lined up, they would wrap around the Earth twice (and then some)! That’s over 60,000 miles of tubes all wound up tightly to fit into the body, sending blood and nutrients to parts of the body that need them. Arteries are thicker than veins and send blood away from the heart. They’re typically filled with oxygenated red blood cells. Veins, on the other hand, send blood towards the heart, carrying deoxygenated red blood cells. Because veins have less pressure pushing blood in the right direction than arteries, they need to have valves that open and close and work against gravity to help keep the blood flowing.

Ever wondered what your blood is actually made up of? After all, it’s not just an abstract red liquid. Blood is composed of a number of things, mainly red blood cells, white blood cells, platelets, and plasma. Firstly, red blood cells are in charge of delivering oxygen. In the lungs, oxygen moves through the tissue and into capillaries, ready to be snatched up by the red blood cells.

Then, the blood is returned to the heart and sent to wherever the body needs it. Once the oxygen is dropped off, carbon dioxide made by tissues is released into the bloodstream and attaches itself to the oxygen. The blood cells then return to the heart and lungs to release the carbon dioxide and pick up new oxygen, restarting the cycle. White blood cells are centered more in your immune system, and attack foreign substances that your body senses. Platelets are in charge of forming clots in the blood, and while this might not sound like a good thing, without them we would bleed out from a mere paper cut! Finally, plasma is the nutrient and hormone delivery system that our body needs to function properly. Without those vital nutrients and hormones, we’d die!

Now that we’ve learned about what’s inside our blood, we can understand why cardiovascular fitness is important for our health. This type of exercise, which increases your heart rate and gets the blood pumping, has shown to increase the count of red blood cells and the volume of plasma in the blood when at rest. An increase of red blood cells means more oxygen can get delivered to working areas, which while you’re exercising, is mostly your muscles. This increases the amount of energy the muscles can output, making them work more efficiently. An increase in plasma at rest means an increased blood flow to the muscles and a decrease in heart rate. All of this comes back to your VO2 max and how efficiently your body utilizes oxygen.

An excellent way to train your VO2 max is with interval training, a form of exercise that increases your heart rate for a short time (usually around two or three minutes) followed by a resting phase of equal or slightly less time, in which your heart rate is able to slow down.

This interval style of training allows you to increase your heart rate for longer periods of time, rather than keeping it high for a shorter period without rests. Incorporating just 20 minutes of interval training three times a week into your exercise routine may result in some of the benefits listed above. Give it a go and see for yourself!

Maddy has worked in the health and fitness industry for 5 years. She has a bachelors in Exercise Science and has recently received her Masters in Exercise Physiology. She has worked with a wide demographic of clients as a Personal Trainer and loves helping people reach their goals and continue to grow.  She is an outdoor enthusiast and dedicates her workouts to rock climbing, hiking and whatever new experiences may come her way.

Main Photo Credit: 4 PM production/; Second Photo Credit: angellodeco/; Third Photo Credit: fizkes/