Biochemical Markers During High-Intensity Interval Training - Term Paper Example

Biochemical markers during high intensity interval training Introduction Biomarkers act as indicators of various biological processes that take place in the body systems under normal conditions. Biomarkers are used in the study of biological changes that one may be interested in; they can be regarded as potential indicators of whether a given biological process ever took place or not. One area where the use of biomarkers can be applied is in the study of changes that occur during high intensity exercises. During any form of exercises, energy is consumed in order to maintain the activity of the muscles. During this process, a number of changes that can be identified using biomarkers occur (Schmalbruch 87). In order to understand the potential biomarkers that can act as indicators of changes taking place during intensive exercises, it would be necessary to understand first how body muscles obtain the energy that they require to keep muscles running. Fueling the muscular system The main source of fuel for the muscles can be obtained from foods eaten. Food nutrients are converted into ATP through a series of biochemical processes (Werner & Sharon 375). These biochemical processes take place through one of the three main energy systems in the body. The three systems include phosphagen energy system, glycolytic energy system and mitochondrial respiration energy system. The intensity and the period the exercises last can be considered as the two main factors that determine the process to be used to generate energy (Mary & Sharon 561). Phosphagen Energy system This system, also called the immediate energy system, refers to the system used during short bursts of exercise such as making a 100 meter sprint. The energy system does not require oxygen supply for it to make energy (Sharon & Denise 456). This makes phosphagen energy system to be considered as an anaerobic energy system. During this process, the immediate energy required for high intensity exercises is obtained from the ATP already present in the system. The ATP present in the muscles can only support about one second of the high intensity exercise. This implies that ATP must be made available in order to keep the muscle activity running during high intensity exercises (Schmalbruch 233). This can be achieved through a reaction that involves creatine phosphate (CP) and adenosine diphosphate (ADP) that combine to form ATP. Creatine phosphate can be described as a high energy compound; the process combining the two is catalyzed by creatine kinase. Creatine is a natural product readily synthesized in the liver, kidneys and the pancrease and is later transported to various body tissues via the blood stream. Within the cells, creatine is phosphorylated to produce phosphocreatine through a reaction catalyzed by several creatine kinases. The latter replenishes ATP in the muscles. This is achieved through phosphocreatine donating its phosphate group to ADP to produce ATP through a reaction catalyzed by creatinase. The highest percentage of creatine in the body occurs in skeletal muscles of type 2 fibers. Presence of reduced levels of phosphocreatine results to lower levels of ATP while high levels of phosphocreatine lead to high levels of ATP (Peter & Wayne 68). The body cells can store about six times more CP than ATP. Therefore, CP can be regarded as the main source of immediate energy. The body can also generate immediate energy through a reaction catalyzed by adenylate kinase (Jack et al. 306). In this reaction, an ATP molecule is obtained from two ADP molecules but energy obtained through this reaction is considered to be insignificant compared to ATP and CP present. The energy generated through the phosphagen system can only sustain muscular activities for only 5-10 seconds, which calls for additional sources of energy (Diane & Williams 182). Glycolic Energy System This is the process involved in the breakdown of glucose into pyruvate through a series of biochemical processes to produce energy inform of ATP. The process can also be referred to as glycolysis or the lactic acid system. This energy system is a 10 steps pathway that is catalyzed by a number of enzymes. Glycolic enzymes include hexokinase, isomerase, phosphofructokinase, aldolase, kinase, mutase, enolase and pyruvate kinase. These enzymes act on glucose and other intermediate substrates that are involved in the formation of ATP. Glycolic pathway does not require the direct use of oxygen, but this does not imply that it only occurs in the absence of oxygen (Sherwood 512). Glycolic pathway can occur with or without oxygen that, together with the activity in question, determines how the pyruvate produced will be used. In cases where there is enough supply of oxygen, pyruvate generated under these conditions goes to the mitochondria. Pyruvate enters the TCA cycle which is a series of enzyme catalyzed reaction that is responsible for producing ATP. Glycolysis marks the first step in the aerobic breakdown of carbohydrates. A clear example where such a condition occurs is during low intensity exercises (Schmalbruch 257). Anaerobic glycolysis takes place in situations where the oxygen demands exceed the supply. This process is also referred to as fast glycolysis and may be common during high intensity exercises that may be done for a few minutes. This process is marked by the accumulation of byproducts, which include lactate and hydrogen ions. The presence of hydrogen ions is responsible for cellular acidosis and the fatigue experienced by people under such conditions. The presence of lactate has shown to be beneficial since it provides sufficient energy for some groups of muscles (Bagshaw & Richard 62). Mitochondrial respiration This metabolic process occurs when there is enough oxygen supply to meet the necessary demands for a certain activity. As the name suggests, the process occurs in the mitochondria. Mitochondria respiration becomes the main source of ATP when the body system is subjected to moderately high intensity exercises that last for several minutes. Compared to the other two anaerobic energy systems, aerobic glycolytic and mitochondria respiration systems are able to produce energy slowly (Mary & Sharon 482). During mitochondrial respiration, pyruvate previously activated during the aerobic glycolysis phase is broken down through a series of enzymatic reactions in the TCA cycle to produce ATP. Other substrates used to generate energy during this process include lipid and amino acid derivatives. The latter are used during prolonged exercises upon the exhaustion of carbohydrate sources. Carbohydrates are otherwise the main sources of energy and can supply about 40-60% of the total energy requirements. Factors that lead to fatigue High intensity exercises cause fatigue in most cases, especially when a person has not yet adapted to the exercises. In most cases, fatigue is caused by the bodys failure to meet the metabolic demands exerted by low supply of oxygen or lack of certain essential minerals required for muscle activity. Major factors include glycogen depletion, lactic acid and low calcium levels (Mary & Sharon 567). Glycogen depletion Glycogen stored in muscles acts as the first source of energy during strenuous exercises. This stems from the fact that it is the immediate readily available source of energy in the muscles. Glycogen is broken down through the process of glycogenolysis which is catalyzed by glycogen phosphorylase to produce glucose-1-phosphate. G-1-P undergoes through the glycolic pathway to form ATP. The level of glycogen in the muscles decreases as the demand for energy increases. After the glycogen is fully depleted, less energy is produced, and a person starts to suffer from fatigue (Peter & Wayne 73). Lactic Acid High intensity exercises call for a high supply of oxygen, and in most cases, the body cannot meet the high demands. In such situations, the body may respire anaerobically for it to produce energy. During the process of anaerobic respiration, lactic acid is produced as one byproduct of anaerobic respiration. In situations where the body is unable to remove the lactic acid, it starts to accumulate in the body system. Accumulation of lactic acid causes an increase in the blood PH, which is the main factor that causes pain and fatigue during high intensity training (Sherwood 247). Calcium Calcium can be regarded as the main mineral responsible for contraction of muscles. Low levels of calcium in the system result to limited force of contraction. Calcium plays a key role in the sliding of muscle filaments during the process of muscle contraction. The two main muscle filaments (myosin actin) can only attach to each other in the presence of calcium. Lack of sufficient calcium inhibits the process of muscle contraction resulting in fatigue (Sherwood 177). The body should be regularly subjected to high intensity exercises in order to overcome these challenges. Prolonged exercises allow the body to increase levels of glycogen and ability to clear lactic acid from the system (Jack et al. 324). Muscle fiber adaptations to high intensity exercises As one continues to engage in high intensity exercises, the muscles increase in size, a condition referred to as hypertrophy. Transient hypertrophy occurs as a result of accumulation of fluids from blood plasma in muscular spaces (Sugi 398). Chronic hypertrophy, on the other hand, refers to increase in muscular size as a result of prolonged resistance to strenuous exercises. In such situations, cross-sectional areas of muscle fibers may increase by 20%-45%. Muscle hypertrophies result from an increased number of thicker actin and myosin filaments, increased myofibrils, increased sarcoplasm and increased number of connective tissues around the muscle fibers (Bagshaw & Richard 257). Conclusion The process of synthesizing energy that is required for proper functioning of the muscular system is marked by a cascade of events. Each process involved in the synthesis of energy generates products which can be used as biochemical markers during high intensity interval training. Examples of potential biomarkers include lactic acid, ATP, ADP, calcium, phosphocreatine, glycogenolysis and glycolysis. These biomarkers act as potential indicators of changes, which occur during high intensity exercises and can be relied upon when carrying out studies involving such exercises. Works Cited Bagshaw, Clive & Richard, David. Muscle Contraction. New York: Springer, 1993. Print. Diane, Gill & Williams, Lavon. Psychological Dynamics of Sport and Exercise. Chicago: Human Kinetics, 2008. Print. Jack, Holmes, Wilmore, David, Costill, Williams & Larry, Kenney. Physiology of Sport and Exercise. Chicago: Human Kinetics, 2008. Print. Mary, Campbell & Shawn, Farrell. Biochemistry. Chicago: Cengage Learning, 2011. Print. Peter, Karpovich & Wayne, Sinning. Physiology of Muscular Activity. Michigan: Saunders, 1971. Print. Schmalbruch, Henning. Skeletal Muscle. New York: Springer, 1985. Print. Sharon, Plowman & Denise, Smith. Exercise Physiology for Health, Fitness, and Performance. New York: Lippincott Williams & Wilkins, 2007. Print. Sherwood, Lauralee. Fundamentals of Human Physiology. New York: Cengage Learning, 2011. Print. Sugi, Haruo. Sliding Filament Mechanism in Muscle Contraction: Fifty Years of Research, Volume 565. New York: Springer, 2005. Print. Werner, Hoeger & Sharon, Hoeger. Lifetime Physical Fitness and Wellness: A Personalized Program. 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