ZOO2AP — Cardiorespiratory Response to Exercise Questions Essay Example
ZOO2APP: Cardiorespiatory Response to Exercise Questions
Section 1 – Blood Pressure
Pulse pressure is the difference between systolic and diastolic pressure readings and reflects the force that the heart produces every time the heart contracts. Pulse pressure increases with light exercises and heavy exercises causes pulse pressure to increases more.
Arterial blood pressure elevates linearly with increase in exercise from light to heavy intensity exercise. As more amount of blood is pumped from the heart, the blood pressure increases within the blood vessels transporting the blood with every heart beat. As exercise starts, the cardiac output rises and blood flow is pushed from the body organs to the muscles. Blood flow to the lungs also rises because of the elevated activity of the right ventricle pumping blood to lungs (Lee & Lee 2015).
Figure 1: Blood flow to the organs at rest and during exercise
Section 2 and 3 – Respiratory and Heart rate (3Qs)
Mathematical relationship between respiratory rate, tidal volume and minute volume (ventilation) is: Cardiac output = stroke volume x heart rate
Stroke volume increased in accordance with exercises since the body requires more oxygen and this is obtained from the blood. The increase of stroke volume was in accordance to the type of exercise. Due to the increase of the stroke volume, cardiac output increases concurrently with the increasing heart rate and therefore the body starts to work harder from rest to during exercise (Lee & Lee 2015)
Minute ventilation increased during light and heavy exercises. The heavier the exercise; the higher the minute ventilation was. This is due to increase in breathing rate and tidal volume. Increased ventilation led to increased oxygen consumption because increased oxygen demands increase ventilation. The most efficient breathing strategy is to breathe more during exercises (Lee & Lee 2015)
Section 4 — ECG (2Qs)
During exercise, there was a decrease in RR interval while the heart rate increased.
Q-T interval was significantly shortened during exercise. This can be attributed to the fact that an increase in heart rate while exercising results to shortening of diastole and systole.
Section 5 – Oxygen consumption (Fick equation)
Question 1 (a)
Where CO is the cardiac output
VO2 max = Q(CaO2-CvO2)
CO is cardiac output,
Ca = arterial oxygen content,
Cv2 = venous oxygen content
VO2max refers to the maximum oxygen consumption that can be utilized per minute and hence represents any person’s upper limit of aerobic metabolism. VO2max increases when the cardiac output or oxygen is availed to the working muscles. Another way where oxygen consumption to the working muscles increases is by increased the A-VO2 difference where there is increased oxygen delivery and improved efficiency whereby working muscles utilize the available oxygen for energy generation. VO2 max is affected by the chemical capacity of muscles to utilize oxygen in breaking down fuels along with the capacity of cardiovascular and pulmonary systems to carry the oxygen to the muscles (Lee & Lee 2015)
Question 1 (b)
CO = 21,000
Ca — Cv2 = 14
And so 21,000 = VO2/14
And hence VO2 = 21,000 × 14 = 294, 000 L. min
Lee Jae & Lee Bang. PR Interval Behavior During Exercise Stress Test. Korean J Intern Med. 10(2), 2015, pp: 137–142.
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