Trainability of underwater breath-holding time.
From diving practice we know that breath-holding time (BHT) can be increased by training. This examination was set up to illuminate whether BHT underwater can be trained decisively in a short period of time. The authors investigated whether physiologic or psychological aspects are the main constituents of the above-mentioned BHT phenomenon. BHT and the "onset point" of involuntary respiratory movements of 64 subjects were registered after deep inspiration and immersion in ca. 1 m. Two different tests were set up: (I) 2 breath-holds per day on 5 consecutive days, (II) 5 repeated breath-holds with pauses of 3 min in between. BHT of the first test was shorter underwater than in similar experiments in air; the increase of BHT underwater was distinctly higher (series II: 160%). Thirty percent of the subjects inequivocally showed respiratory movements (group 1), 31% did not reach the "onset point" (group 3). In group 1 BHT was considerably higher than in group 3. In group 1 the mean time span without respiratory movements rose by 14% in series I and by 233% in series II, whereas the time span with respiratory movements rose by 105% and 119%. These results confirm and quantify the good trainability of BHT underwater. Two processes cause this increase: the increase in time span without respiratory movements probably by unconscious hyperventilation and the increase in time span with respiratory movements through psychological adaptation by suffering the need to breathe.
D000328:Adult; D004242:Diving; D006801:Humans; D008875:Middle Aged; D010806:Physical Education and Training; D012119:Respiration; D012718:Set, Psychology; D013997:Time Factors