Cardiovascular exercise has been getting quite a bad reputation lately. It is indeed strenuous, can be long and with such other replacements such as High Intensity Interval Training, Crossfit, Powerlifting and what not. People are quick to ditch a long cardio session for a something better if anything at all, but is cardio really all that bad?


Cardiovascular exercise has been apart of the human experience for thousands of years, both long endurance and shorter, high intensity cardio. From messengers running miles and miles between ancient cities, hunters chasing after animals and people crossing oceans with nothing but ores and the wind. Even today in many parts of the world, endurance running is a part of every day life and not just for athletes.


Cardiovascular endurance, as defined is “the body’s ability to continue exertion while getting energy from the aerobic glycolysis system used to supply the body with energy.”


What exactly does that mean? Well the body utilizes 3 systems to Creatine Phosphate system which is designed for extremely short burst of high intensity exercise (think of Usain Bolt running the 100m). It only lasts for 10-20 seconds before switching over to Anaerobic glycolysis which can maintain moderate-high intensity exercise for 30 seconds up to 2-3 minutes. Finally Aerobic glycolysis kicks in which you can sustain moderate amounts of exercises consistently for an extended period of time. This is the system that burns fat as it’s primary fuel source. The key to remember is, all 3 systems work together in tandem so there is never just one system engaged at a time. However the predominant energy system (CP, Anaerobic or Aerobic) is based on the intensity and duration of the exercise. That’s what determines the primary fuel source for energy and thus what specifically you are training to improve.

Myth #1

  • Cardiovascular Exercise is bad for you, particularly your heart.
    • -For the average person on any level of conditioning, cardiovascular exercise has been shown to improve overall health and reduce the risk of developing coronary, metabolic and pulmonary diseases.
    • -Like anything in the world, too much can have negative effects, a deconditioned person trying to run a marathon with little to no training will likely hurt themselves. Listen to your body and approach your goals with baby steps.
    • -People with heart disease, diabetes, obesity, or high cholesterol need to be more cautious and slow in the approach. While cardiovascular exercise will help reduce these risk factors, too much too soon can have the opposite effect. It is important to consult with a physician prior to engaging in any program if you have any of these risk factors.


Myth #2

  • High Intensity Interval Training (HIIT) is just as good or better than aerobic cardio.
    • -HIIT is a different mode of training than long endurance, aerobic cardio. The two certainly are not exclusive and you will burn fat with both however HIIT doesn’t fully replace regular cardio. In order to run a marathon, you have to put in long hours of running. To do a bike tour, you need to spend hours riding a bike. HIIT cardio is good when you don’t have the time for a longer training session and it’s even better to add in during a long endurance training session. It is not a good replacement for long endurance training if that is your goal.
    • -Adding short bursts of HIIT during a long run, bike ride, swim etc. Is very beneficial to add variety to an otherwise long and boring training session as well as help train the body for more than just “survival” (as in just surviving the long run, bike ride etc.) Nothing feels better than having the energy to sprint across the finish line or to overcome another competitor, getting up when you fall or climbing a hill during a long race.


Myth #3

  • If it gets your heart rate up, it’s cardio right?
    • -Nope.
    • -Remember the definition of cardiovascular exercise? “The body’s ability to continue exertion while getting energy from the aerobic glycolysis system used to supply the body with energy.”
      • –Aerobic glycolysis is always happening, but it takes consistent exercise for 2 or more minutes at a time when your aerobic glycolysis energy system starts to burn fat as it’s primary fuel source. HIIT training and Long Endurance Cardio utilize this system because the bouts tend to last from several minutes to several hours.
      • –Other exercises such as power lifting will get your heart rate up but you will not be able to sustain that level of training for more than a few seconds before resting, That is not cardio, that is power lifting and strength training.


There are many aspects of physical fitness. Muscular Strength, Muscular Endurance, Cardiovascular Endurance, HIIT, Flexibility and Body Composition. For the best physical fitness and health make sure your training program contains all the different components.


By Dirk Smith

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