Cardio or cardiovascular training has been looked at as waste of time in terms of weight or fat loss. Yet, there are enough evidence that show that cardio training has benefit towards fat or weight loss. Cardio training, just like resistance training, has several variations. When you understand these mechanisms, you may rethink of what cardio training is all about.
Let’s say a person weighs 160lb with bodyfat of 25%. This means that the person has 40lb or 18kg of body fat. When you calculate this into calories, the person has about 16,000 calories worth of energy that is stored in our body. If the same person’s daily caloric intake is 2000 calories, the person has 8 days worth of energy stored in their body. So, the question comes, how can we tap into those energy.
Before we go in deep, lets define cardio training and its purpose for a starter.
Defining Cardio Training
When social media talks about cardio training, they are only talking about steady state cardio.
Steady state cardio refers to cardio exercise, such as walking, jogging, cycling, etc. with consistent effort for extended period time usually above 20 minutes. If someone is starting to exercise, this may be a good place to start along with resistance training.
When fitness "experts" considering steady state cardio to be the only type of cardio training shows lack of understanding of what cardio training is or lazy enough not to explain the different training methods within cardio training.
Primary focus of cardiovascular training is to train the cardiovascular system as the name suggests. What does that involve? Let’s start with obvious part. Term cardiovascular is referring to heart and blood vessels. Therefore, main purpose of cardio training is to improve the function of heart and blood vessels.
Something that is less obvious is allowing the body to adapt in 3 different energy system. 1.) ATP-CP system, 2.) glycolysis or lactate system and 3.) aerobic or mitochondrial respiration system. We will discuss on these 3-energy system later, however, the cardio training should be utilizing one or more of these 3 energy system per session.
Commonly known cardio training methods are walking, running, cycling, rowing, swimming and so on. However, when you look at the purpose of cardio training, you can also use resistance training to create cardio benefit. In other words, routine such as, high intensity interval training, Tabata Methods, circuit training, can all be in the category of cardio training.
3 Energy System in Cardiovascular Training
As mentioned earlier, cardio training needs to be involved in usage of one of 3 energy system. Initially, energy system that one should work on is aerobic or mitochondria respiration system. In this energy system, the main energy source is fatty acids, muscle glycogen, and lactate depending on intensity level of the training. When training in this energy system, the performance should be able to sustain for at least 2 minutes. Some of the exercise examples can be steady state cardio, low impact circuit training and so on.
Glycolysis or lactate system utilize muscle glycogen, lactate and ATP-CP as energy source depending on intensity level. Exercise should be sustainable from anywhere between 20 -120 seconds. Some of the exercise examples can be sprint intervals, high intensity interval training, and so on. ATP-CP system utilizes muscle ATP and CP as energy source and work can be sustained from 1-20 seconds. Some of the exercise can be max effort lift, plyometrics, sprints and so on.
It is important to understand that this energy system should not be trained by itself. It is more effective when combining all energy system during the training. For example, you may perform 20yd sprints followed by 2 minutes jog. This is using ATP-CP system first then followed by aerobic system. By doing so you are training the body with max effort movement then to recover from the stress you have created without completely resting.
Combination of energy system may vary from purpose of the training and condition that the person is in.
Adaptation from 3 Energy System Cardio Training
With proper cardiovascular training physiological benefits are 1.) decrease in heart rate, 2.) increase in capillary density, 3.) increase in size and number of mitochondria 4.) increase in lactate threshold.
It is critical to monitor either your heart rate or RPE (Rate of Perceived Exertion). By monitoring it makes the training easier to manipulate the intensity level to either sustain or change which allow the heart rate, capillary, and mitochondria to adapt.
By stimulating and recovering the heartrate, it will get stronger and efficient in sending more blood throughout our body in 1 pump. This is known as stroke volume. There is another terminology called cardiac output, which is amount of blood pumped out of heart per minute. With proper cardio training our body can have higher VO2 (measure of how much oxygen you can breathe in during exercise), Stroke Volume, and Cardiac Output. By doing so our resting heartrate can be lower and still be able to send adequate amount of blood throughout the body.
With heart being able to send more blood per heartbeat, our blood vessel also needs to adapt by increasing in its diameter and creating new pathways (angiogenesis) to enable the delivery of higher volume of blood to the muscles. Imagine you have a street with a traffic jam. There are two possible solutions. One is to widen the road. Second is add new pathways to the destination. This is the adaptation that our body does by exercising on regular basis. Benefit of angiogenesis is not only to send more oxygen to the muscles but also removal of metabolites such as lactic acids and pyruvic acids.
Mitochondria is the organelle that is responsible for the energy production. With a system called Kreb cycle and electron transport chain, mitochondria can create energy from glucose and fat. By performing cardiovascular training on regular basis, mitochondria will go through adaptation by increase in its size and its number, which means they can create more energy to the muscle.
Another adaptation by performing cardiovascular training is increase in lactate threshold. This is dependent on intensity of training. As we get fitter and able to use more oxygen efficiently, our body can rely on using fat as energy source and sparring glycogen. This process is called glycogen sparring. Higher intensity training requires us to use glycogen as energy source which leads to production of lactic acids. Through adaptation to cardiovascular training, the body has capability to increase lactate threshold.
If you workout for the first time, you may have gone through muscle soreness. But after a while, same intensity of workout no longer causes you to fatigue and able to handle higher intensity training. This is adaptation of cardiovascular system and have increase in lactate threshold.
Cardio and Fat Loss
Majority of complain about cardio is it is not effective towards weight or fat loss is because of the adaptation. It is true that once the body adapts to certain intensity of exercise, whether it is cardio or resistance training, only way to get more benefit is by increasing either intensity or volume of exercise. When you look at usage of energy, it is true that same amount of intensity and volume that the body got adapted to may not have significant influence in terms of caloric usage.
However, though, it also means that you can perform the exercise at higher intensity or volume. By able to increase intensity and volume of exercise amount of energy or calorie you will be using will increase. Which means, you will need to change exercise method, intensity, volume every few weeks (usually 4-8 weeks). By doing so, the energy output will be higher, will have stronger muscles and joint, and able to utilize fat as energy source at higher intensity level and can recover from stress faster.
Nutrition, Hydration and Sleep
Since we are on the topic of weight loss, here is a tip. It doesn't really matter how well the exercise is designed. When it comes to weight or fat loss, nutrition, hydration and sleep has to work together with exercise. This is true with building muscle and strength.
Over consumption of food, relative to your daily activity, make the weight loss that much challenging. Before thinking about macronutrient split, work on eating 3 meals with whole food, no snack. If fat loss is your goal, you will need to refrain from consuming sugar especially fructose for it goes straight into your fat. This includes fruits. Nothing wrong with it, but if your plan is to reduce body fat, it is not recommended.
Hydration is another key factor in healthy weight loss. If you are having difficulty drinking a gallon of water, at least drink a glass (8oz) of water before each meal and after getting out of bed. Once you have created this habit, then work up to a gallon a day. Water consumption is not just to quench your thirst but also to maintain pH level in your blood. Even those who are using supplements, it is very important to consume water while taking supplement.
Sleep is probably the one that most people have issues with. Anything less than 7 hours may cause either, cognitive, metabolic, hormonal, cardiac issues which all of these are important in strength building and fat loss. Work on following your sleep schedule and avoid using sleep aids such as alcohol or sleeping pills since they are just sedatives. Sedation is not a sleep. Keeping the room temperature to 65F can also help improve your sleep quality.
When these 3 are working together with exercise, you will make a change in your physique, strength and health.
Cardio or Strength?
This is the question we see on social media and I don't know why people love to compare these. If you are looking to make change you should work on both for they are both important for strength, physique, and health.
Reason why you see these type of question more frequently is because of marketing strategy in fitness industry.
Is cardio training inefficient in weight loss? I don't think so. When done right and pair with strength training, it will have undeniable benefit to your weight loss.
Kota Shimada
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