<p>Underwater swimmers hyperventilate before going under water and take deep rapid breaths in order to do all of the following EXCEPT
(A) increase the oxygen content of the blood
(B) decrease the urge to breathe
(C) decrease the pH of the blood
(D) blow off carbon dioxide
(E) increase the amount of carbon dioxide of alveoli air</p>
<p>I chose the right answer, which was E. My logic was that swimmers hyperventilate in order to bring and store temporarily much oxygen in their body before they go underwater since they know that they cannot come up for air after diving in. Therefore, A and B are correct. Another point to be made is that they are trying to let out carbon dioxide before they jump into water because they are not going to let it out once in the water (not as well as they did in the air at least): thus, D is right. E is the right opposite of what hyperventilation is for because the swimmers are trying to increase the amount of oxygen in alveoli air to supply it to their body via capillaries when swimming in water.</p>
<p>However, my question is: isn’t C a typo? Shouldn’t it be “INCREASE the pH of blood” not decrease? If the swimmers are letting carbon dioxide out, as said in D, they would have less carbonic acid, the form in which carbon dioxide is stored in the blood; less acid means higher pH, so the swimmers are trying to INCREASE the pH of their blood. Aren’t they??</p>
<p>Thanx in advance :D</p>