Freediving is an activity in which a person dives, sometimes to great depth, without the use of scuba gear. the diver must hod his or her breath for the duration of the dive. (the record depth with no equipment such as diving fins, is 101m; the offical record time is over 11 minutes). historically freediving has been used by pearl divers and sponge divers. some freedivers hyperventilate (breathe rapidly and deeply) before diving. hyperventilation can change the concentration of co2 in the blood and may increase the length of time that a person feels like he/she can hold his/her breath. how does hyperventilation affect blood ph? a. it increases co2 and decreases h+ in the blood, increasing phb. it decreases co2 and increases h+ in the blood, increasing phc. it increases co2 and h+ in the blood, decreasig phd. it decreases co2 and h+ in the blood, increasing ph