Introduction11.docx - Abstract Endurance exercise and high altitude are two common ways to improve the exercise performance by adaptations in skeletal

Introduction11.docx - Abstract Endurance exercise and high...

This preview shows page 1 - 3 out of 12 pages.

Abstract Endurance exercise and high altitude are two common ways to improve the exercise performance by adaptations in skeletal muscular cells. The hypothesis that the adaption of muscle metabolism due to exercise training is caused by cellular hypoxia in the muscle tissue will be discussed by comparing the effects of high altitude and exercise training on skeletal muscle. Endurance exercise improves the oxidative capacity in the muscle cells by increased mitochondrial density, increased mitochondrial enzyme activity and a more efficient energy coupling and indicates an adaptation of the energy metabolism. The mitochondrial DNA is regulated by TFAM, which expression is induced by P53. HIF-1 increases the expression of PDK-1, which inhibits the pyruvate dehydrogenase complex (PDHc). The inhibition of PDHc leads to reduced mitochondrial function, what results in an decreased oxygen consumption. High altitude reduces the partial oxygen pressure in blood levels, what causes reduced haemoglobin-oxygen saturation and reduced total oxygen content of blood. To compensate for hypoxic stress, the oxidative phosphorylation reduces and the anaerobe fermentation increases. The glycolytic pathway increases to maintain the cellular ATP levels. This switch is regulated by HIF-1. With this switch, the oxygen consumption reduces. If the mitochondrial density changes remains controversial, although it is clear that the relative subsarcolemmal mitochondrial density is reduced. High altitude and endurance exercise have some effects in common and it is probably is the induced change of energy metabolism caused by a common pathway. Introduction Athletes are looking for the best form of training to improve their performance. There are two common ways to improve aerobic performance: endurance exercise training and staying at high altitude. Both challenges have shown to improve endurance exercise performance, which is generally viewed as the body’s adaptations to environmental alterations to maintain homeostasis (Hoppeler & Vogt, 2001). Exercise training is known to induce adaptations in the cardiovascular system as well as in skeletal muscles. This thesis focuses on the adaptations of the skeletal muscle tissue to exercise training. These muscular adaptations, which will be mentioned later on, might be a response to cellular hypoxia, a condition of insufficient oxygen in the
Image of page 1
cells for the -aerobic energy metabolism. For exercise causes increased oxygen consumption, which results in reduced oxygen levels in the exercising skeletal muscles. (Lindholm & Rundqvist, 2016) Environmental hypoxia at altitude is known as a key environmental stressor that initiate important physiological adaptations in the athlete. Various physiological adaptations that occur after a prolonged (> 28 days) stay at high altitude may be exploited to yield significant improvements in sea-level athletic performance (Flaherty, O’Connor, & Johnston, 2016). An important adaptation to altitude exposure is an improved oxygen carrying capacity of the blood. In response to hypoxia, the kidneys produce erythropoietin (EPO). EPO promotes
Image of page 2
Image of page 3

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture