Training in Extreme Conditions Essay Example
Training in Extreme Conditions Essay Example

Training in Extreme Conditions Essay Example

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  • Pages: 9 (2378 words)
  • Published: August 5, 2017
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Training involves obtaining knowledge, skills, and abilities through vocational or practical instruction that is directly relevant to specific useful competencies. The goal of training is to enhance capability, capacity, productivity, and performance.

Exercise in Wales is influenced by several factors, including intensity, duration, frequency, and environment. When exercising, the body requires more oxygen and substrates for skeletal muscles. This leads to the removal of metabolites and carbon dioxide. The demands for these lead to changes in metabolic, cardiovascular, and ventilatory functions through chemical, mechanical, and thermal stimuli. Muscle contraction is initiated by adenosine triphosphate (ATP), a high-energy phosphate molecule. Initially, ATP and Phosphocreatine provide energy for the muscles before activating other metabolic processes. To meet the increased need for oxygen during exercise, pulmonary ventilation increases by raising r


espiratory rate. Enzymes such as ATPase can utilize the energy stored between ADP and Pi bonds.

Hydrolysis involves water and is the process where each ATP molecule releases 7.3 K cal (30.7 kj) of energy. The acetylate kinase reaction provides another energy source by converting two molecules of ADP to Amp and ATP (Stokes). Phosphocreatine, stored in the musculus, serves as a high-energy source for skeletal muscle and supplies energy during intense activities like sprinting for the first 10 seconds before being depleted. However, it is crucial as an initial energy source before other metabolic processes commence.

(Stokes) The resynthesis of ATP from energy-dense substrates, such as glycolysis, involves the conversion of animal starch and glucose into two pyruvate molecules in the presence of O. The pyruvate then enters the Krebs rhythm via acetyl coA. Each turn of the Krebs rhythm produces H bearers that enter the ETC and eventually donate

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H+ to form H2O. This allows the ETC to proceed. However, without O, the ETC cannot continue, leading to a build-up of pyruvate and potentially stopping glycolysis and ATP synthesis. Luckily, pyruvate can accept the H bearer and form lactic acid, producing only 3 moll ATP per molecule of animal starch even without O. In contrast, complete breakdown of animal starch through glycolysis, the Krebs rhythm, and the ETC produces 39 ATP per molecule of animal starch. (Stokes) Fatty acids have a higher energy density than animal starch and there are large stores of fat in adipose tissue. All energy stored as fat is stored as animal starch, causing an increase in body mass of 50 Kg.

Fatty acids are broken down and enter the Krebs cycle and electron transport chain (ETC). A fully oxidized fat produces 129 ATP molecules. The rate at which fat is resynthesized is too slow to be significant during high intensity training. During exercise, ventilation may increase from values around 5-6 liters/min to > 100 liters/min. In an average young male, resting oxygen consumption is about 250 ml/min, and in an endurance athlete during intense exercise, it may reach 5000 ml/min (Stokes). Changes in arterial pH, PO2, and PCO2 values during exercise are typically small. The increased reliance on glycolysis leads to an accumulation of lactic acid, which initially results in an increase in PaCO2.

Ventilation increases rapidly at the beginning of exercise and then gradually rises at a slower pace (Stokes). The demand for oxygen in active skeletal muscles is much greater compared to when the muscles are not being used. Normally, blood flow to resting muscles is around 2-4 ml•100

g muscle?1 min?1, but can reach up to approximately 100 ml•100 g muscle?1 min?1 during intense physical activity. These alterations in circulation cause an augmented blood supply to the muscles, resulting in increased cardiac output and oxygen utilization.

The body converts energy from food into muscular work, with a maximum efficiency of 20-25%. The remaining energy is released as heat, which raises body temperature. This increase in temperature stimulates sweat glands and boosts metabolism and blood flow to the skin. As a result, sweating occurs and heat is dissipated.

Training in Heat (Rg)

This study investigates the impact of high temperatures on the human body, its adaptation to higher temperatures, stages of illness caused by excessive heat, and precautions for exercising in hot conditions. The human body typically strives to maintain an optimal temperature range for optimal functioning, with an average normal body temperature of 37°C. An increase in body temperature by 2°C to 3°C usually does not have negative consequences.

Astrand.P (1986) states that if the body's core temperature goes beyond 40°C to 41°C, it can result in various heat-related problems. During exercise, the body produces heat through metabolism and muscle contraction, leading to an increase in core temperature. This activates the thermoregulatory mechanism, which works to restore homeostasis by improving blood flow to cool the skin and increasing sweating. Sweating helps in evaporating heat and decreasing the core temperature. Consequently, these processes enhance cardiovascular strain due to increased blood flow to the skin and muscles while also reducing blood plasma volume due to sweat loss.

When blood flow is redirected to the skin and muscles, it stimulates a cardiovascular response causing a decrease in stroke volume. This reduction

in stroke volume necessitates an increase in heart rate to maintain cardiac output. In order to ensure adequate blood supply to the skin and working muscles, a higher heart rate is needed. As the blood reaches the hypothalamus, the core body temperature starts to rise, leading to signals being sent from the hypothalamus to reduce exercise intensity in other parts of the body (Phil Wallace, 2013).

Exerting in hot climates without proper acclimatization can lead to a severe condition known as "Heat illness," which is categorized into different stages based on the pathological events that occur.

  1. Heat Spasms: This stage occurs when drinking water without salt during episodes of thermal dehydration. It is characterized by painful muscle spasms.
  2. Heat exhaustion: Heat exhaustion happens due to sweat loss from exposure to high environmental heat or strenuous work. Symptoms include elevated body core temperature, weakness, fatigue, discomfort, anxiety, dizziness, and headache.
  3. Heat faint: Cardiovascular failure occurs at this stage due to decreased venous return to the heart caused by excessive fluid loss. Symptoms include dizziness, fainting, and pale face.
  4. Heat stroke: The most severe heat-related disorder that can be fatal. It is characterized by core temperatures exceeding 40°C with hot and dry skin indicating impaired thermoregulation. Additionally, it is associated with delirium, convulsions or coma suggesting impaired central nervous system function.

According to Yamazaki (2012), heat acclimatization refers to the body's adjustment to temperature changes. This process typically occurs within the first 10-15 days, with the most significant changes happening in the initial 3 to 4 days. Heat acclimatization offers several benefits: it improves endurance exercise performance in hot conditions and enhances comfort during physical activity.

During heat acclimatization, various adaptations occur. These include

an increase in plasma volume of around 10-12%, an earlier onset of sweating, a higher sweat rate, reduced salt loss through sweating, decreased blood flow to the skin, and increased synthesis of heat shock proteins.

To ensure safety when exercising in hot environments, precautions should be taken. This includes assessing individuals' history of previous heat illnesses and allowing a period of seven to ten days for acclimatization.

Instruct participants to wear suitable clothing during the acclimatization period. Regularly measure the WBGT index. Encourage participants to sufficiently replenish fluids. Record participants' body weight before and after practice and matches.

Identify vulnerable participants. Constantly monitor and supervise participants for signs of heat illness. Players should have unlimited access to water” . (International Hockey Federation (FIH), 2010)

Training in Cold Conditions (Tyler)

Exercising in cold temperatures is a complicated concept.

When getting ready to exercise in the cold or during the cold season, there are a few things to consider. These include changes in metabolism and cardiovascular system, thermal aspects, and adaptations. Choosing the right diet for exercising in cold conditions can be difficult. Current research has not found one specific diet that is better than others, whether it's high in carbohydrates, fats, or proteins. However, a study by Thorp et al. (1990) showed that consuming a high carbohydrate diet of 600g/day for three days led to higher work output compared to a normal diet of 300g/day over the same period.

According to Doubt and Hsieh (1991) and Jacobs et al. (1984, 1985), research has demonstrated a significant connection between exercise performance in cold environments and carbohydrate consumption. These studies have shown that when exercising in cold temperatures, venous lactate concentrations increase due to the

inverse relationship between muscle temperature and glycolysis. At -2°C, lactate levels were higher compared to +24°C and tended to rise at a slower rate, indicating a delay in lactate release associated with temperature. The measurements taken at the end of each incremental increase in workload were used as the basis for these findings (Therminarias et al., 1989).

The body's ventilation increases when exposed to colder surroundings, but the disparity in ventilation between cold and heated environments lessens with higher exercise intensity (Therminarias et al. 1989). Our lungs inhale oxygen and exhale carbon dioxide during respiration. Nonetheless, heightened ventilation may result in lower levels of end-tidal carbon dioxide.

Working in cold environments can lead to impaired cognitive function if the body retains high levels of CO2 (Cooper et al. 1976). When exposed to cold, our body activates cutaneous thermal receptors that send pain signals to the central nervous system through afferent signaling.

The body's response to increased VO2 during exercise in a cold environment involves two mechanisms. According to studies by Nadel (1984), Park et Al. (1984), Rennie (1988), and Sagawa et Al. (1988), the first mechanism is a change in body heat throughout the entire structure. As mentioned by Pendergast (1988), the second mechanism is a reduction in net mechanical efficiency. When there is a change in body heat, the body reacts through negative feedback.

When the body experiences a change in temperature on the skin, thermic receptors detect it and send a signal to the central nervous system. The central nervous system then decides how to restore balance. The brain communicates with the hypothalamus, which sends a message to the muscles causing them to shiver or contract rapidly.

This action generates heat and raises the body's core temperature. As homeostasis is achieved, the feeling of cold decreases as the hypothalamus reduces its heat-promoting function. It is important to consider our body's efficiency in performing certain actions when predicting how cold temperatures will impact us.

Blomstrand et al. (1986) found that when muscles are cold, their contractile force decreases while the demand for kinetic energy stays constant. As a result, the body may have to activate more motor units to generate the required work output. Moreover, being exposed to cold weather leads to notable peripheral vasoconstriction and subsequently raises blood pressure.

Low temperatures can affect cardiac output by increasing intrathoracic blood volume through peripheral vasoconstriction (Pendergast 1988). This increase in intrathoracic volume is shown by greater increases in stroke volume (McArdle et al. 1976) or overall body insulation (Rennie 1988). Research has proven that the enlargement of left ventricular end-diastolic and end-systolic dimensions during rest and exercise occurs as a result of increasing intrathoracic blood volume (Sheldahl et al. 1984).

Exposure to cold temperatures while exercising can lead to injuries, such as non-freezing cold injuries or cryopathy. These injuries often occur in the distal appendages, which rely on blood flow to maintain a suitable local temperature due to limited heat production (Doubt; A; Francis 1989). Our peripheral systems use a negative feedback technique, involving vasoconstriction and vasodilation, to restore a suitable local temperature (Rusch et al.).

The text refers to several sources including Cymrus, J. in a web log message retrieved from [hypertext transfer protocol://](hypertext transfer protocol:// in 2013, Stokes, K. retrieved from [hypertext transfer protocol://](hypertext transfer protocol:// with no specified date, and Ali Al-Nawaiseh, M.B., in an

unspecified year.

The article "Physiological Responses of Distance Runners during Normal and Warm Conditions" is published in the Journal of Exercise Physiology online, 12.

The book "Textbook of Work Physiology" by Astrand.P, K. was published in New York by the McGraw-Hill Companies in 1986.

The International Hockey Federation (FIH) has publications in 2010.

Competition in hot and humid environments. Guidance competition in hot and humid environments, 10.

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  • St Catherine of Aragons, Ontario, Canada.

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    In their study, T.J. Doubt et al. (1989) examine the hazards associated with cold water.

    Another study by W.D. McArdle et al. (1976) investigates the metabolic and cardiovascular adjustments during work in air and water at 18, 25, and 33°C.

    Y.S. Park et al. (1984) focus on the decrease in body insulation with exercise in cool water.

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    New York, NY: McGraw-Hill.

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