Explain how lactate levels respond to different training intensities and how these responses relate to other immediate physiological adaptations during exercise. Use specific examples to support your answer. (8 marks)
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- During low-intensity exercise, lactate levels remain relatively stable and close to resting values as the aerobic energy system can meet the body’s energy demands
- As exercise intensity increases to moderate levels, there is a slight increase in lactate production, but the body is still able to remove or utilise most of the lactate produced
- During high-intensity exercise, lactate levels rise significantly as the body increasingly relies on anaerobic glycolysis for energy production
- The sensation of muscle burning during intense exercise is partly due to the accumulation of hydrogen ions associated with lactate production
- Rising lactate levels coincide with increases in heart rate, as both respond to the increasing energy demands of the working muscles
- Ventilation rate also increases in response to higher exercise intensities and is indirectly related to lactate accumulation, as the body attempts to supply more oxygen
- For example, a basketball player performing repeated sprints during a game would experience elevated lactate levels, accompanied by increased heart rate and breathing rate, which all contribute to the feeling of fatigue
- After exercise ceases, lactate levels gradually return toward baseline as the body clears lactate through various mechanisms, including conversion back to glucose in the liver
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Sample Answer
- During low-intensity exercise, lactate levels remain relatively stable and close to resting values as the aerobic energy system can meet the body’s energy demands
- As exercise intensity increases to moderate levels, there is a slight increase in lactate production, but the body is still able to remove or utilise most of the lactate produced
- During high-intensity exercise, lactate levels rise significantly as the body increasingly relies on anaerobic glycolysis for energy production
- The sensation of muscle burning during intense exercise is partly due to the accumulation of hydrogen ions associated with lactate production
- Rising lactate levels coincide with increases in heart rate, as both respond to the increasing energy demands of the working muscles
- Ventilation rate also increases in response to higher exercise intensities and is indirectly related to lactate accumulation, as the body attempts to supply more oxygen
- For example, a basketball player performing repeated sprints during a game would experience elevated lactate levels, accompanied by increased heart rate and breathing rate, which all contribute to the feeling of fatigue
- After exercise ceases, lactate levels gradually return toward baseline as the body clears lactate through various mechanisms, including conversion back to glucose in the liver