K28. systemic responses to exercise
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K28. systemic responses to exercise

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K28. systemic responses to exercise K28. systemic responses to exercise Presentation Transcript

  • EXERCISE PHYSIOLOGY Department of Physiology Faculty of Medicine Universitas Sumatera utara
  • Systemic Responses to Exercise
  • NEUROMUSCULAR FUNCTIONS AND ADAPTATIONS TO EXERCISE  Exercise maintains neuronal health by improving blood flow to the brain and by increasing brain levels of growth factors that promote optimal function of neurons.  Recent study in humans has concluded that exercise improves brain function and reduces the risk of cognitive impairment associated with aging.
  • NEUROMUSCULAR FUNCTIONS AND ADAPTATIONS TO EXERCISE  Humans skeletal muscle can be divided into several different classes based on the histochemical or biochemical characteristics of the individual fibers.  Neural adaptations: ↑ maximal motor unit recruitment ↑ synchronous recruitment of motor units
  •  SO motor units are recruited first during incremental exercise, followed by a progressive increase in FOG and FG motor unit recruitment as exercise intensity increases.  Both endurance and resistance exercise training have been shown to promote a fast-to-slow shift in skeletal muscle fiber types but does not result in complete transformation of all fast fibers.  Training adaptations: increases in muscle size from hypertrophy and hyperplasia.
  • METABOLIC RESPONSES TO EXERCISE: INFLUENCE OF DURATION AND INTENSITY Short-term, Intense Exercise • During high-intensity, short-term exercise (i.e., two to twenty seconds), the muscles’ ATP production is dominated by the ATP-PS system. • Intense exercise lasting more than twenty seconds relies more on anaerobic glycolysis to produce much of the needed ATP. • High-intensity events lasting longer than forty-five seconds use a combination of the ATP-PC system, glycolysis, and the aerobic system to produce the needed ATP for muscular contraction.
  • METABOLIC RESPONSES TO EXERCISE: INFLUENCE OF DURATION AND INTENSITY Prolonged Exercise  The energy to perform prolonged exercise (i.e., more than ten minutes) comes primarily from aerobic metabolism.  A steady-state O2 uptake can generally be maintained during prolonged, low-intensity exercise.
  • METABOLIC RESPONSES TO EXERCISE: INFLUENCE OF DURATION AND INTENSITY Incremental Exercise • The maximal capacity to transport and utilize O2 during exercise (maximal oxygen uptake, or VO2 max) is considered to be the most valid measurement of cardiovascular fitness. • Indeed, incremental exercise test (also called graded exercise test) are often employed to determine a subject’s cardiovascular fitness. • These tests are usually conducted on a treadmill or a cycle ergometer.
  • • Oxygen uptake increase in linear fashion during incremental exercise until VO2 max is reached. • The physiological factors that influence VO2 max include: – The maximum ability of the cardiorespiratory system to deliver oxygen to the contracting muscle. – The muscle’s ability to take up the oxygen and produce ATP aerobically.
  • CARDIOVASCULAR FUNCTIONS AND ADAPTATIONS TO EXERCISE  With the start of exercise, cardiovascular function changes by: ↑ Heart rate ↑ Ejection fraction ↑ Stroke volume ↑ Cardiac output ↑ Redistribution of Q in favor of contracting skeletal muscle ↓ Vascular resistance ↑ Muscle blood flow
  •  Muscle Contraction  Venous Return  End Diastolic Volume  Contractility  Stroke Volume  Heart Rate  Cardiac Output  Cellular Respiration Sympathetic Stimulation  Muscle Vascular Resistance  Muscle Blood Flow  a-vO2∆  Oxygen Extraction  Oxygen ConsumptionAcute cardiovascular adaptations that combine to increase oxygen consumption during exercise
  • CARDIOVASCULAR FUNCTIONS AND ADAPTATIONS TO EXERCISE  Cardiovascular adaptations to training are extremely important for improving endurance exercise performance, and preventing cardiovascular disease  The more important of these adaptations are: ↑ Plasma volume ↑ Red cell mass ↑ Total blood volume ↓ Systolic and diastolic blood pressire ↑ End diastolic dimensions and ventricular volumes ↑ Maximal stroke volume ↑ Maximal cardiac output
  • Training For Long -Term Endurance  Plasma Volume  Red Cell Mass  Blood Volume  Venous Return  Ventricular Volume  End Diastolic Volume  Maximal Stroke Volume  Muscle Capillary Density  Maximal Muscle Blood Flow  Oxygen Delivery  VO2max Exercise to VO2max  Maximal Cardiac Output Chronic adaptations of the CV system after exposure to training for long term endurance. Adaptations are related to their affect during both maximal & submaximal exercise
  • Training For Long-Term Endurance  Plasma Volume  Red Cell Mass  Blood Volume  Venous Return  Ventricular Volume  End Diastolic Volume  Stroke Volume  Sympathetic Stimulation  Heart Rate Submaximal Steady State Exercise Chronic adaptations of the CV system after exposure to training for long term endurance. Adaptations are related to their affect during both maximal & submaximal exercise
  • PULMONARY ADAPTATIONS TO EXERCISE  After the onset of exercise there is: A rapid ↑ in ventilation A similar rapid ↑ in pulmonary blood flow An improved VE vs Q relationship in the lung ↑ Lung compliance Airway dilation and ↓ resistance to air flow  The lungs and pulmonary circulation do not express the degree of long-term adaptations to exercise. The improvement are more determined by muscular and cardiovascular function.
  • Endocrine Adaptations to Exercise