Three Myths About Cardio, Busted!

​By Dirk Smith, MSc, SDL (He/Him). 

Cardiovascular exercise has been getting quite a bad reputation lately, it is indeed strenuous and can be long and boring. It is often overlooked in favor of more trendy fitness programs including HIIT and Crossfit. People are quick to ditch a long cardio session for a something better or straight up lose motivation to do 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 everyday life and it’s not just for athletes.
 
Cardiovascular endurance, as defined by the American College of Sports Medicine (ACSM) as "any activity that uses large muscle groups, can be maintained continuously, and is rhythmic in nature." Most common types of cardio include walking, running, swimming, cycling, and rowing.
 
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, the Citric Acid Cycle kicks in, using fat as the primary fuel source, you can sustain moderate amounts of exercises consistently for an extended period of time. The Citric Acid Cycle takes place within the mitochondria of the cells, which makes it the “powerhouse of the cell.”
 
Within the ACSM definition of cardio, which includes maintaining activity continuously the predominant system used during cardiovascular exercise is Aerobic glycolysis
 
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.

Myth #2

• High Intensity Interval Training (HIIT) is better and should replace 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 either. 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.) HIIT is also a great way to add variety and diversity to your regular routine to keep things interesting.

Myth #3

• If it gets your heart rate up, it’s cardio right?
  • Nope.
  • Remember the definition of cardiovascular exercise? "any activity that uses large muscle groups, can be maintained continuously, and is rhythmic in nature."
    • Aerobic glycolysis doesn’t happen until your already consistently exercising 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 maintain 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. The best training programs include a health combination of all those components, even when if they aren’t all your favorites!

​By Dirk Smith