3.5. Cardiopulmonary adaptation during change in the body position and during physical exercise.

Question 1

I. Basics
1. What is the source of energy during heavy exercise?

Answer 1

the biochemical resource like creatine phosphate exhausts in seconds and anaerobic resources last for a few minutes.
-> For long lasting energy provision, oxidative energy is needed which helps muscle tissue ATP level to remain unchanged.

Question 2

I. Basics
1. what is oxygen debt?

Answer 2

0henomenon where after completion of exercise, respiration remains the above resting level in order to replenish the stored oxygen used up during the exercise.
- Alactacid oxygen debt: O2 uptake to restore phosphagen system = 3.5 L - Lactic acid oxygen debt: O2 uptake to oxidize the lactic acid = 8 L

Question 3

II. Cardiopulmonary adaptation during change in the body position

Answer 3

When body position changes from supine to standing:
=> CVP is ↓, so Preload ↓, so stroke volume (SV) also ↓ (heterometric regulation)
=> Cardiac Output (C.O.) ↓
=> MAP ↓
=> High pressure baroreceptor

Question 4

II. Cardiopulmonary adaptation during physical exercise.
1. What are the Cardiopulmonary adaptations that need to make during physical exercise?

Answer 4

1. Arterial O2 and CO2 partial pressure
2. Venous pCO2
3. Muscle and joint receptors
4. Cardiac output and pulmonary blood flow
5. Hemoglobin affinity

Question 5

II. Cardiopulmonary adaptation during physical exercise.
2. How is Arterial O2 and CO2 partial pressure adapted?

Answer 5

• The pO2 and pCO2 do not change during exercise
• Increased ventilation and more efficient gas exchange ensures that the O2 levels do not fall and the CO2 levels do not rise in the arterial blood
• The arterial pH can change due to the lactic acid produced during exercise, but that is the extent

Question 6

II. Cardiopulmonary adaptation during physical exercise.
3. How is Venous pCO2 adapted during physical exercise?

Answer 6

• The venous CO2 partial pressure increases, because skeletal muscle is increasing the amount of respiration and thus more CO2 is produced
• In order to get rid of this extra CO2, the ventilation rate increases to avoid an increase in arterial pCO2

Question 7

II. Cardiopulmonary adaptation during physical exercise.
4. How are Muscle and joint receptors adapted during physical exercise?

Answer 7

• These receptors send signals to the medullary inspiratory center to increase ventilation due to increased movement of the body
• They are activated early in exercise

Question 8

II. Cardiopulmonary adaptation during physical exercise.
5. How is Hemoglobin affinity adapted during physical exercise?

Answer 8

• As many of the inhibitors of Hb are produced during exercise (H+, CO2, increased temp), the hemoglobin dissociation curve shifts to the right, because the affinity for the oxygen is decreased
• the P50 also increases (the pO2 at which Hb is 50% saturated ~normal = 26mmHg)

Question 9

II. Cardiopulmonary adaptation during physical exercise.
6. What are the events of anaerobic threshold?

Answer 9

Question 10

III. Adaptation to change in body position
1. What happen when When body position changes from supine to standing?

Answer 10

Question 11

III. Adaptation to change in body position
2. Make a schematic diagram of adaptation to change in body position

Answer 11

Question 12

III. Adaptation to change in body position
3. What happen if the blood pressure drop in a patient?

Answer 12

So: if the blood pressure drops of a patient (e.g. pain can lead to vasodilation): it may worth to turn the chair in supine position to ensure proper brain perfusion.

There is one exception: patients with cardiac disease!
In this condition the ↑ of preload (from supine position) may lead to overstretch of the heart muscle, thus the strength of ventricular muscle decreases. These patient also will tell that they prefer sitting or standing than laying