Energy Sources for Physical Exercises Essay

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Health Fitness Human Performance

One of the most important parts of an athlete's training regime is nutrition because of its role in human performance. Athletes need to focus on nutrition because the failure to ingest adequate calories can contribute to a lack of vital macro and micro nutrients. Moreover, nutrition is a crucial element in any athlete's training regime given the influences of food on a person's physical mankind. Throughout history, certain foods have been regarded as essential in preparation for strenuous physical activity or exercise. As part of focus on nutrition, athletes need to consider various factors that contribute to nutrition in relation to physical activity and exercise. Some of these important considerations include certain types of food and food sources that help in preparation for physical activity, heath, fitness, and human performance.

What is glycogen? Why is it important for exercise? 5. What are some activities that are high energy expenditure? Why do they expend more energy?

Glycogen can be simply defined as the storage form of carbohydrates and glucose in human beings and animals (Millan par, 8). In addition to being a huge multi-branched polymer of glucose, glycogen is usually stored in form of glucose. This form of glucose is accrued in reaction to insulin and disintegrated into glucose through reacting to glucagon. Generally, glycogen is largely stored in the muscles and liver and offers the body with a readily available energy source in case of decrease in the levels of blood glucose. Glycogen is important in exercise since it is one form of stored energy that is usually preferred because it is an energy source for the brain. The significance of glycogen in exercise is the ability of glucose to provide energy for cells when there is no oxygen such as during anaerobic exercise. Therefore, glycogen provides a readily available source of energy for the body that helps during exercise. While physical activity is the only factor fueling energy expenditure, there are some activities that are high energy expenditure such as running, intense cycling, and weight-bearing activities. These activities expend more energy because they engage large muscles in an ongoing, systematic way.

6. Name several factors that are known to influence the availability and use of energy sources during exercise.

Energy that is utilized during exercise is basically supplied from two major sources i.e. fats and carbohydrates. While fat supplies energy stored around the body, carbohydrates supply energy in the form of glycogen that is stored in the muscles. When exercising, an individual or athlete utilizes both energy sources since at high intensity, the energy source is carbohydrate whereas fat is the dominant source at low intensity. The presence of restrictions to the quantity of carbohydrate that can be stored in the muscles implies that high intensity work cannot be maintained for long periods while low intensity work can be sustained for long because of large amount of fat stored in the body. Some of the factors that influence the availability and use of energy sources during exercise include duration of exercise, intensity of exercise, the initial levels of muscle glycogen, the level of exercise training, and increase of carbohydrates during the exercise.

1. List 5 food sources of carbohydrate. When do carbohydrates enhance sports performance in terms of length of events? Provide an example of a 30 gram carbohydrate snack?

As previously mentioned, carbohydrates is one of the important sources of energy, especially for high intensity work. There are various food sources of carbohydrates including vegetables, fruits, brown rice, oatmeal, and whole wheat products. Foods containing carbohydrates have been identified as having the most vital effect on exercise performance. Carbohydrates improve sports performance with regards to length of events when they provide necessary energy for ATP synthesis. This is important because high exercise intensities associated with sports increased demand for ATP synthesis. An example of a 30 gram carbohydrate snack is a fruit and grain bar, 1 English muffin, a banana, animal crackers, 20 baked tortilla chips, 1 cup sugar-free pudding, and 6 graham cracker squares.

2. What type of athlete benefits from carbohydrate loading? What type of athlete does not? 3. How do you carbohydrate load? What are the steps involved?

Carbohydrate loading is a strategy that is used by some athletes to maximize energy or glycogen storage in the muscles. Athletes that benefit from carbohydrate loading are those involved in endurance sports like marathon running. Apart from marathoners, the other athletes who benefit from carbohydrate
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loading include triathlon participants and football players. Therefore, athletes who do not benefit from carbohydrate loading are those who are not involved in endurance sports or exercises. The process of carbohydrate loading involves the use of a regimen that was developed in the 1980s through research. The regimen, which removes the depletion phase, entails increased carbohydrate intake and reduced training at least three days before an event ("The Role of Carbohydrates in Exercise" par, 8). In some cases, carbohydrate loading involves normal diet combined with light training until the eve of the event.

5. What is the main source of energy for prolonged athletic events? Is this fuel utilized more effectively in trained athletes?

As previously mentioned carbohydrate and fat are the basic sources of energy though carbohydrate acts as the body's principle source of energy. The other source of energy for the body is protein, which generates a minimal amount under ordinary conditions. Prolonged athletic events usually involve low intensity work or exercises that are sustainable by the body rather than high intensity work. The main source of energy for prolonged athletic events is carbohydrate, which is mostly utilized in high intensity exercises but is also usually used at low exercise intensities. Carbohydrate acts as the main source of energy for prolonged athletic events because fat simply cannot offer the required energy for ATP synthesis. Trained athletes utilize this fuel more effectively since their diet incorporates intake of carbohydrates. Their use of this fuel effectively is also attributed to the fact that their training regimen not only focuses on different types of exercises but also emphasizes and involves proper diet for carbohydrate intake.

6. Can carnitine supplements enhance fat metabolism and physical performance?

Carnitine plays an important role in the metabolism of fatty acid through transferring long-chain fatty acids into mitochondria for improved beta-oxidation (Heinonen, p.109). In the past few years, supplementary carnitine has widely been used to enhance fat metabolism and physical performance despite the absence of indisputable support for the practice. This implies that there is no scientific evidence for athletes or healthy individuals to utilize carnitine supplements to enhance exercise performance. Moreover, athletes do not have an enhanced need for cartinine since they are not at risk of suffering from cartinine deficiency. While it is possible for individuals and athletes to enhance muscle cartinine content through diet, fat metabolism and physical performance is largely dependent on the intensity of exercise, which results in improved energy usage and performance. Despite the lack of scientific evidence, carnitine supplements can still enhance fat metabolism and physical performance.

1. Explain protein's role as a fuel source. Is it significant? What does excess protein in the body become?

Even though carbohydrate and fat act as the body's primary sources of energy, protein is also an energy source though it provides a minimal amount under normal situations. Protein's role as a source of energy is evident in the late stages of prolonged exercise, particularly endurance activities. During this stage or period, muscle glycogen stores reduce, which forces the body to break down amino acids found in skeletal muscle protein into glucose that provides a minimal portion of the required energy. Moreover, the role of protein as a fuel source is evident when every day diet is insufficient in total carbohydrate or calories. In this case, the body depends on protein for its energy needs resulting in disintegration of lean muscle mass. Therefore, the role of protein as a fuel source is significant when daily diet lacks enough carbohydrates or calories. However, excess protein in the body is stored as fat, which may contribute to weight gain, high cholesterol, and reduced brain and liver function.

2. What are the physiologic functions of protein? Is animal protein the healthiest protein for the diet? How should animal and plant proteins be consumed in the diet?

Proteins are compounds in the human body that contain amino acids, which are made of oxygen, carbon, nitrogen, and hydrogen. Despite the dangers of excessive protein in the body, there are some physiologic functions of protein. Some of the physiologic functions of protein include structure, movement, immunity, communication, energy, and transport and storage. The other functions of protein in the body include fluid balance, acid-base balance, and chemical reactions. Animal protein is the healthiest protein for the diet because this source of protein has a tendency to provide all the needed amino acids. The other sources of protein are not the healthiest for the diet because they lack at least one important amino acid. However, the consumption of…

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Works Cited

Heinonen, Olli J. "Carnitine and Physical Exercise." Sports Medicine 22.2 (1996): 109-32. Print.

Millan, Inigo S. "The Importance of Carbohydrates and Glycogen for Athletes." TrainingPeaks. Peaksware Inc., 17 Jan. 2013. Web. 02 June 2015. <>.

"The Role of Carbohydrates in Exercise and Physical Performance." FAO Corporate Document Repository. Food and Agriculture Organization of the United States, n.d. Web. 02 June 2015. <>.

Tarnopolsky, Mark A. "Effect of Caffeine on the Neuromuscular System -- Potential as an Ergogenic Aid." Applied Physiology, Nutrition, and Metabolism 33.6 (2008): 1284-289. Print.

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