What Is Cardiorespiratory Fitness And How Can I Improve It?


When it comes to physical performance and overall physical well-being, cardiorespiratory fitness is a term that cannot be overlooked. Cardiorespiratory fitness, also referred to as cardiorespiratory endurance, cardiovascular fitness and cardiovascular endurance, is a very vital indicator of how physically fit and healthy we are. In fact, there is growing evidence that cardiorespiratory fitness is potentially a stronger predictor of mortality than established risk factors such as heart disease and diabetes.

What is cardiorespiratory fitness? Cardiorespiratory fitness is simply a measure of how well your body performs during a period of sustained physical activity. It measures your circulatory and respiratory systems’ ability to transport oxygen to muscles during a prolonged exercise and how well your muscles are able to utilise the supplied oxygen.

Cardiorespiratory fitness therefore relies on how well the heart, lungs and muscles work together to keep fatigue at bay during a sustained or prolonged physical activity. An effective and efficient cardiorespiratory system therefore requires fitness of multiple parts of the body, especially the lungs, heart, blood vessels and muscles.

Having strong, healthy heart and lungs, together with healthy blood vessels ensures an efficient supply of oxygen to your muscles during a period of moderate to high-intensity physical activity. This enables you to exercise for a prolonged period without getting tired.


How Is Cardiorespiratory Fitness Measured?

A cardiorespiratory fitness test is done by measuring metabolic equivalents (METs) and or maximum oxygen uptake, also known as VO2 max. Physically fit individuals can also do submaximal tests with a qualified fitness instructor to determine level of cardiorespiratory fitness.

  • Metabolic Equivalents (METs): Done in a clinic, hospital or laboratory setting, this test measures the ratio between the energy expended during a physical activity and the energy expended while resting. This involves measuring the amount of oxygen the body uses while at rest. This gives a picture of one’s level of intensity and oxygen uptake during a physical activity.
  • Maximum Oxygen Uptake (VO2 Max): Carried out in a lab controlled setting in the presence of a clinician and or exercise physiologist, this test is widely considered the best way to assess cardiorespiratory fitness. This test determines the maximum amount of oxygen the body is capable of using during high intensity physical activities. The VO2max test typically involves running on a treadmill or pedaling on a stationary bicycle as fast possible while your heart rate and oxygen consumption are being measured. The heart rate and oxygen consumption are measured with the help of a chest strap (or other similar body attachments) and a face mask connected to a special gas meter. The volume of oxygen you can use during the hardest minute of your exercise is considered your VO2 max. The higher the number in your VO2 test, the higher the maximum oxygen uptake.
  • Submaximal Exercise Tests: Unlike the above two means of measuring cardiorespiratory fitness, this method does not require a clinic or lab controlled setting. Submaximal exercise tests include the 2.4 km (1.5 mile) run test, the Astrand treadmill test and the multistage bleep test. Scores here are determined based on your ability to function rather than on the volume of oxygen your body can use. These tests are not as accurate as laboratory tests of cardiorespiratory fitness, however, they do give a good estimate of your level of fitness, and each assessment comes with its own strengths and weaknesses.

Benefits Of High Cardiorespiratory Fitness

An individual’s level of cardiorespiratory fitness is an indicator of how aerobically and physically fit that individual is. The benefits of having a high level of cardiorespiratory fitness goes beyond just being able to sustain a long period of high intensity physical activity.

The name ‘cardiorespiratory’ is a combination of two of the human body’s vital systems, the cardiovascular system and the respiratory system. The cardiovascular system consists of the heart, blood vessels and blood. This system pumps blood and oxygen around the body. The respiratory system on the other hand is controlled by the lungs and also includes the air passages that bring oxygen to the lungs from outside the body.

The cardiovascular and respiratory systems work hand-in-hand to supply the human body’s cells with needed materials and get rid of waste.

Benefits of having a high level of cardiorespiratory fitness therefore include:

  • Various studies suggest people with higher cardiorespiratory fitness are less likely to develop high blood pressure compared to those with lower cardiorespiratory fitness.
  • Maintaining a higher cardiorespiratory fitness enables the body to have less bad cholesterol (also known as low-density lipoprotein or LDL) and more good protein (also known as high-density lipoprotein or HDL).
  • Less bad cholesterol, less risk of blood clots and healthy elastic arteries allowing more blood flow leads to less risk of coronary heart disease.
  • Maintaining a higher cardiorespiratory fitness enables the lungs to work efficiently and deliver more oxygen to the blood.
  • The higher your level of cardiorespiratory fitness, the stronger your heart muscles get. The heart is then able to take in and carry more oxygen, resulting in an increase in the number of red blood cells and hemoglobin.
  • A high cardiorespiratory fitness enables the nerves to slow down resting heart rate and builds more heart muscles. This enables the heart to work efficiently by pumping more volume of blood with each beat and distribute oxygen better.
  • Having a high level of cardiorespiratory fitness generally means that an individual is able to perform and sustain a rigorous or high-intensity exercise for a longer period of time without getting tired.
  • A good level of cardiorespiratory fitness means you are healthy and fit enough to take part in physical activities that will help you burn calories, lose weight and keep it off.


How Can I Improve My Cardiorespiratory Fitness?

To improve cardiorespiratory fitness, you should increase how active you are on a daily basis and perform exercise activities that raise your heart rate and keep it up for a prolonged period of time.

The key point to remember here is how regular and long you exercise for. Exercising regularly and continuously increasing the level of difficulty of your cardio activity is what you need to keep pushing your heart rate.

Having a medium to high intensity workout session, at least 3 times a week is ideal. You should be aiming for about 60 minutes for a medium-intensity workout session or 30 – 40 minutes for a high-intensity session. You should strive to push yourself a little further each time you exercise. Continuous progression is very vital!

One person’s medium-intensity might be another’s high-intensity. So it is very important to choose the duration and training intensity that suits your fitness level.

In order for your cardiorespiratory fitness to improve, you must subject your cardiorespiratory system to physical demands greater than it is used to. Just going through the motions during workout sessions simply won’t be enough!

You need to keep an eye on the intensity, duration and frequency of your workout sessions. The intensity and duration must challenge your cardiorespiratory system, and the frequency must be good enough to maintain continuous progress.

Activities ideal for improving and maintaining cardiorespiratory fitness include:

  • Running
  • Cycling (either stationary or on a real bicycle)
  • Swimming
  • Rowing
  • Boxing
  • Racquet sports
  • Football/Soccer
  • Basketball
  • Nordic skiing



Exercises you can perform in the comfort of your home to boost cardiorespiratory fitness include:


Safety First!…..

Fitness levels vary from one person to another. As stated earlier, one person’s moderate-intensity might be another’s high-intensity. If you are someone who hasn’t had an active lifestyle or had/have fitness concerns, especially heart and lung problems, you should speak to your doctor before attempting to improve your cardiorespiratory fitness.

Once given the all clear to commence your fitness journey, you should consider starting with some few minutes of moderate-intensity, 2 to 3 times a week before ramping up the intensity, duration and frequency of your workout sessions.

Always remember to stay hydrated by regularly taking sips of water throughout each workout session.

Final Thoughts…

Improving cardiorespiratory fitness is essential for improving overall health. It does not only improve how well the human body circulates and utilises oxygen, it also improves physical performance and has a positive correlation with lung and heart health.

With an improved level of cardiorespiratory fitness, hypokinetic diseases such as diabetes, heart disease, stroke and obesity are kept at bay. This should hopefully be more than enough reason to get rid of your sedentary lifestyle. Shouldn’t it? Let’s go…….

Your time to start getting active is now……it is better late than never!

Please feel free to leave comments, questions and suggestions in the comments section below. Thank you.

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