ENERGY SYSTEMS AND HOW THEY WORK.

August 30, 2024

ENERGY SYSTEMS AND HOW THEY WORK.

HOW IS ENERGY FORMED IN THE BODY?

Anabolism and catabolism are words that most of us might have heard especially in conversations concerning metabolism. A glimpse of them on paper might seem to be these complex terms but are they really?

Anytime we eat food, let say a balanced diet, the digestion process starts from the mouth all the way to the colon before excretion. During this process, a lot of things take place. A great example is separation of different macros i.e. carbs, proteins and fats. This happens so as the body can break them down into simpler substance i.e. carbs into glycogen, proteins into amino acids and fats into glycerol & fatty acids. This conversion process is known as Catabolism. In their simplest forms, it becomes easy for the body to utilize them where necessary. Amino acids are converted and utilized as protein synthesis which is essential for muscle repair. Glycogen is converted into a complex molecule and utilized as energy synthesis hence becoming the primary source of energy. Fatty acids and glycerol are converted into lipid synthesis which acts as substitutes of energy synthesis when there is a depletion in glycogen. This process is known as Anabolism.

A depletion in the primary and the substitute source of energy could result in conversion of amino acids to energy synthesis. This explains why during starvation for a prolonged period of time like in the "Shakahola Massacre", guys seemed to have little to no muscles on their frame. The previous muscle mass had to be converted into energy for basic survival of the bodily organs like energy for the heart to pump blood.

What are these forms of energy systems in the body?

As seen, food is the primary source of energy. This becomes a key factor in the sustainability of the energy levels. The energy system can be classified into three:

ATP-PC energy system - It's the immediate form of energy system. It's made up of two component as the name suggests i.e. adenosine triphosphate (ATP) and phosphate creatine (PC). They are stored in the muscle for short but explosive type of activities. Ideally, they are meant to last between 10-15 seconds depending on the nature of the activity. This makes it ideal for athletes who are into movement that embrace such process, like powerlifting.

It takes about 2-3 min for it to be fully replenished after depletion. This gives insights on why it's necessary to take longer breaks in between a heavy-lifting set or session.
Lactic acid energy system - Also known as Glycolytic or Anaerobic energy system, is the secondary most form of energy provision. The primary source being glucose in the liver and in the muscle cells. The break down produces ATP which is the currency of energy in muscle cells. During the break down process, there is formation of pyruvate, which is converted into lactic acid once oxygen is limited. This result in a burning sensation as a result of the after-effect of accumulation of lactic acid. It's meant to last between 30 sec-2 min, making it ideal for explosive but slightly longer activities like sprinting.

It comes into play after the depletion of ATP-PC energy system. Engaging in workouts like HIIT sessions which entails a short but explosive type of set up will help amplify our explosive power.
Aerobic Energy system - also known as the oxidative system, uses oxygen as a catalyst to convert fats into ATP. It's the most reliable source for prolonged type of activities like marathon running.

There are a few processes that amount to this form of energy system. Glycolysis tend to be the initial process where macros like carbs and fats are broken down to ATP. Krebs cycle is the second ,where pyruvate is further broken down to generate electron carriers. Lastly is the Electron transport chain, where electron drive a large production of ATP. For endurance athletes, carb loading days or a day prior is important. This ensures that their glycogen stores are fully equipped for the awaited task.

The heart's bpm plays a key role in all these forms of energy system. This is because it's the primary source of oxygenated blood. The blood doesn't make ATP but it helps in the transportation of key ingredients i.e. glycogen and oxygen that are crucial in the production of ATP.

At 90-100% maximum heart rate (Zone 5) , an individual will be utilizing the ATP-PC energy system.
At 80-90% maximum heart rate (Zone 4), the individual will be operating on Lactic energy system.
At 50-70% maximum heart rate (Zone 1-2), he/she will be operating on Aerobic energy system.

Here is a simple calculation assuming this individual was 30 years of age,

The estimated maximum heart rate for this 30 year old would be:
220−30=190 bpm
So, for her to tap into the Lactic acid energy system, her bpm should