Analyse the relationship between exercise intensity and the immediate responses of heart rate, stroke volume, and cardiac output during a training session. (6 marks)
--- 14 WORK AREA LINES (style=lined) ---
Show Answers Only
Sample Answer
Heart rate response:
- At the beginning of training, heart rate increases rapidly from resting levels as the body immediately responds to the demand for increased blood flow to working muscles.
- As exercise intensity increases from light to moderate, heart rate continues to rise in proportion to the intensity of the exercise to deliver more oxygen to muscles that need it.
- At high training intensities, heart rate approaches its maximum, with the rate of increase slowing as it nears the individual’s maximum heart rate.
Stroke volume response:
- When training begins, stroke volume increases from resting levels as more blood returns to the heart and the heart contracts more forcefully.
- As intensity increases to moderate levels, stroke volume continues to increase due to stronger heart contractions and greater venous return from active muscles.
- At high training intensities, stroke volume typically levels off and may even slightly decrease when heart rate becomes very high, limiting the time for the heart to fill between beats.
Cardiac output response:
- Cardiac output, which is heart rate multiplied by stroke volume, increases progressively with exercise intensity to meet the increasing oxygen demands of working muscles.
Show Worked Solution
Sample Answer
Heart rate response:
- At the beginning of training, heart rate increases rapidly from resting levels as the body immediately responds to the demand for increased blood flow to working muscles.
- As exercise intensity increases from light to moderate, heart rate continues to rise in proportion to the intensity of the exercise to deliver more oxygen to muscles that need it.
- At high training intensities, heart rate approaches its maximum, with the rate of increase slowing as it nears the individual’s maximum heart rate.
Stroke volume response:
- When training begins, stroke volume increases from resting levels as more blood returns to the heart and the heart contracts more forcefully.
- As intensity increases to moderate levels, stroke volume continues to increase due to stronger heart contractions and greater venous return from active muscles.
- At high training intensities, stroke volume typically levels off and may even slightly decrease when heart rate becomes very high, limiting the time for the heart to fill between beats.
Cardiac output response:
- Cardiac output, which is heart rate multiplied by stroke volume, increases progressively with exercise intensity to meet the increasing oxygen demands of working muscles.