Each and every function of our body requires energy; should that be muscle contraction, food digestion, our respiratory system; walking around the supermarket or firing those neurons when taking end of year exams.
Just like a vehicle requires fuel; should this be diesel or petrol, our bodies run on a substance known as ATP (Adenosine Triphosphate) and this energy ‘currency’ is the only fuel our body can utilize to complete its functions. Our muscles store a very limited amount of ATP, subsequently lasting only a few seconds, requiring re-synthesis of ATP through its fuel source. ATP does not only provide you with energy for day to day functions – it was also partly responsible for your birth, as ATP provides energy to the ‘tail’ of a sperm cell to move allowing it to reach the egg.
First it is important to understand that we have three types of energy systems, which use different fuel sources to generate ATP. Moreover, it is important to note that we are never exclusively using one energy system at a time. The three systems include Creatine Phosphate (CP), Lactate or Anerobic Glycolysis, and the Aerobic System.
The Creatine Phosphate (CP) energy system is based purely off a chemical reaction and, as such, does not require oxygen, fat or carbohydrates to be synthesized. Utilisation of this energy system is exhausted after a maximum of 10 seconds and you can observe the CP system under maximal exertion activities; including the 100 meter sprint, a golf swing, high jump – or running for your bus on a late Monday morning start! CP/ATP stores are 50% restored after 30 seconds and fully restored after approximately 5 minutes rest. When you see those heavy-weight gym-jockeys standing around the gym chatting and staring at their watch… if they are doing it correctly, they are timing their recovery period to replenish the right energy system to promote the training zones that they are performing in – despite further being distracted at their own image in the mirror!
Our Lactate system, aka Anaerobic Glycolysis system, uses glycogen – by form of carbohydrates, which are stored in the muscles. The lactate system serves two primary purposes 1) to provide the body with energy once our activity exceeds the CP system, with near maximal effort, and 2) to provide energy to the body when activities exceed that of what the aerobic system can provide. You may have heard of the ‘lactic-acid burn’ after someone pulls off that excruciating high intensity set at the gym. Lactate acid is a by-product of the lactate system – and its production is worthy until an imbalance or build up of lactate is present and the cardiovascular system is unable to disperse it from the muscles. It is at this point the person slows down or ceases activity all together. This build up is also known as OBLA (onset of blood lactate accumulation). You can observe the lactate system in a range of activities – typically high intensity which only last for up to three minutes, for example a 400 meter sprint or a fairly ‘active’ 3 minute round of boxing (keep in mind that we are never exclusively in one system). While the lactate system can sustain energy production for up to 3 minutes, it requires from 20 minutes to 2 hours for full recovery (breakdown of the lactate acid).
Our aerobic system produces ATP from the complete breakdown of carbohydrates, fat and protein. The Aerobic system dominates when there is sufficient oxygen in our cells to match our activity levels – this is from a person’s resting state to low/moderate activity i.e. walking around the supermarket. ATP is generated in the Aerobic system through a process called mitochondria. This is the intake of oxygen, fatty acids (fat) and glucose (carbohydrates) that are then transformed into CO2, H20 and ATP. Carbohydrates are the ‘preferred’ energy source for the aerobic system as it is most quickly converted, although releasing less energy per molecule than fat and alcohol. The H20 and CO2 are waste products and easily removed – H20 through sweat and CO2 via the lungs.
So as we said, we are never exclusively using one system at a time - for example: during a 5000-meter race, the first 10 seconds will use the ATP/CP system. During the next 20-30 seconds there will be a transition from the CP to Lactate system. After 30 seconds and up to two minutes the lactate system will be used. Between two and five minutes there will be a transition from the lactate to the aerobic system and beyond five minutes the aerobic system will be used. A final sprint will combine both the aerobic and lactate systems (Davis, Kimmet & Auty, 1986).
Why is this all useful to know? This is something most if not all individuals attempting to improve their health and fitness level should be aware of. It helps you understand the sources of energy, how to repair and recover the energy systems and how best to utilize them. We can also train and develop these systems (Lactate and Aerobic Systems) to have a higher threshold, in order to sustain and recover through these systems more effectively. This can be achieved through Anaerobic and Aerobic interval training. We also use energy systems to help promote the training zones that we are operating in. As we mentioned earlier, those gym-jockeys were utilizing their CP systems for maximal lifts in the gym – this is somewhat typically related to strength and power training which in this case looking to also promote not just the CP energy system but their fast twitch type-2 muscle fibers.
Understanding how your body operates is a key first step in taking total control over your personal health and fitness. When you stop in to Tribal this week, use this 'knowledge for power' to help increase your muscular strength and endurance in line with your health and fitness goals.