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Losing Weight With Cardio - Working Smarter, Not Harder!

person smiling and runningThe concept of weight loss is often a very intimidating thought, and for many different reasons. One of the biggest challenges when beginning this journey, is the very first step. Where should I start? Some people would say “it starts in the grocery store”, others will immediately recommend a treadmill, while some extremists will recommend an approach that closely resembles voluntary starvation.

This article is not intended to provide you with a nutrition plan or exercise routine. Rather than adding to the thousands of blog posts on weight-loss protocols, I want to speak to the mechanisms of losing weight via exercise. We will put aside diet and nutrition for a moment, not because I believe exercise is more important, but because optimizing health requires a fine-tuned balance between exercise and diet that is far-too complex for one blog post.

I often see people running vigorously and sweating out of every pore in hopes of losing some weight. If you have ever attempted to lose a significant amount of weight, you may have noticed that improvements occur very quickly at first, and then the improvements slowly taper and perhaps even plateau. This is one of the most frustrating realizations for anyone who has been consistently dedicated. So why does this happen?

Let’s Talk About Energy – a Simplified Explanation

Muscles and organs have different functions and as such, the requirements for optimal function may also be different. The same applies to different cells of the body. Even the location of the organ is very important. The brain is a good example of an organ that requires a lot of energy, but also requires a very specific way of getting the energy.

ATP (adenosine triphosphate) is the universal source of energy for your body. It is created from the breakdown of certain nutritional compounds such as sugar, fat, protein, and others. The primary sources of energy are actually carbohydrates and fat. Let’s talk about these two:

Carbs (or carbohydrates) are the molecules often called “sugar compounds”. Your body directly breaks these down into glucose, which is then broken down into ATP and becomes the main source of energy for your body. Excessive energy from carbs becomes stored within tissues such as the liver, skeletal muscle or turned into fat.

While this sounds like a ‘good’ thing, too much energy from glucose breakdown can also be a problem. An abnormally high level of glucose within your blood is one of the first diagnostic criteria for diabetes.
Fats are a very unique and an important molecule in the body. Although they often have a bad reputation, we wouldn’t be who we are without fats. Some types of fats include cholesterol, which is then used to create testosterone and other important hormones that heavily influence our body’s function. To use fat as energy, it needs to be turned into fatty acids first. An abundance of fatty acids can become stored as fat tissue. There are different types of fatty tissue, but the most abundant is what we call “subcutaneous fat”, aka the fat we are trying to burn!

For the purpose of this blog, we are concerned about subcutaneous fat. This is the form of stored energy that is most readily available to be used as energy. In order to efficiently achieve weight loss, we need to maximize our ability to use fats rather than carbohydrates.

Let’s Talk About Exercise

To exercise, we need energy. Similar to a car needing gasoline or your laptop needing electricity to function. So you’re likely wondering: when does the body use fats and when does it use carbohydrates as a primary source of energy?

It really comes down to your body’s requirements and demands during exercise! For example, just by being alive, you need energy. Your body knows this, so it uses easily available energy-producing systems. You have likely noticed that with performing more strenuous exercise or activity, we fatigue faster than when we are doing light activity. This is because with increased activity intensity, we use more carbs than fatty acids. For the purpose of this blog, I will simplify the above paragraph by summarizing that whenever we use more carbs than fatty acids, we fatigue quicker.

The way we produce and transport energy occurs through three systems:

  • Aerobic uses oxygen to produce energy (ATP). The oxygen comes from each breath you take. This system prefers to use fatty acids and can provide energy for the longest out of the three systems.
  • Anaerobic (without air or oxygen, more specifically) creates energy without the need of oxygen, hence “an-aerobic”. This system will primarily use carbohydrates and can provide energy for a moderate amount of time.
  • Creatine phosphate system is the quickest way to produce energy (ATP), but has a very limited quantity available. This energy system can only provide energy for very short periods of time, such as a 50 meter sprint.

So to summarize, the aerobic system is primarily functioning during long-lasting but low intensity activities such as walking, very light cycling and more. The creatine phosphate system is used for very quick and short bursts of high-intensity exercises such as sprints, high jump, power lifting and more. Lastly, the anaerobic system kicks in once the aerobic system is reaching full capacity. This capacity is determined by the intensity of the exercise. Therefore, we begin to see the anaerobic system used for energy whenever we are jogging, running, cycling, and more.

Since different energy systems use different sources of energy, in order to best utilize fats for energy, we need to train within the appropriate level of intensity that best correlates with the type of energy system that uses fats!

To maximize fat burning, you need to be exercising at a low-intensity that you can sustain for a long period of time. The higher the intensity, the less fat-burning systems you will use!

In the case of running, if you can’t maintain your current pace for longer than 30-60 minutes, you are most likely using anaerobic energy systems, which prefers carbohydrates. Fat is best used during a light pace where you can maintain a conversation. – Not the gold standard for prescribing activity, but it’s a decent reminder.

The key thing here is that the level of intensity is dependent on the level of fitness of the individual! Remember the plateau we discussed at the beginning? When this happens, it most likely means that you’ve improved your level of fitness and can now maintain a faster pace while still primarily using fats as energy.

The Good News

Fat is best used for energy with light activity. So remember, if you can’t keep the pace for at least 2 hours, you should probably slow down. The better news? You can get tested to identify at which heart rate and intensity you should be performing your physical activity at. With this test, you will clearly see WHEN your body is using fats and when its using carbohydrates. This information is unique to you because it is measured while you exercise. This test is called your VO2 max along with other cardiovascular measures.

The best news? Ottawa Health: Performance and Rehabilitation offers VO2 max testing, resting metabolic rate testing, and other cardiovascular testing. Through these tests, we will have the most up-to-date technology to maximize your weight loss journey; not by working harder, but by working smarter!

Ottawa Health: Performance and Rehabilitation is one-of-a-kind facility. Our multi-disciplinary clinic is working on becoming leaders in injury prevention, longevity, and optimizing health. Stay tuned for our next blog where we will discuss VO2 testing!

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