Breath-hold performance during cold water immersion: effects of psychological skills training.

Introduction: Accidental cold water immersion (CWI) is a significant cause of death, particularly in those who are immersed in rough water or forcibly submerged such as in a ditched and inverted helicopter. The marked reduction in maximal breath-hold time associated with CWI, part of the 'cold shock' response, significantly increases the risk of drowning. However, the response is highly variable between subjects. This experiment tested the hypothesis that part of this variability is due to psychological factors. Methods: There were 32 subjects who completed 2 2.5-min, head-out immersions in 11 degrees C water, separated by 7 d. Between immersions, subjects were matched on initial maximum breath-hold time on immersion (BHwater) and allocated to either a psychological intervention group (PIG) or control group (CG). PIG (n = 16) subjects each undertook a psychological skills intervention comprising 4 interlinked training sessions covering goal-setting, arousal regulation, mental imagery, and positive self-talk; CG (n = 16) continued normal daily activity. Results: Psychological intervention significantly increased BHwater on immersion in the PIG vs. the CG [mean (SD); CG BHwater immersion 1: 24.01 (6.72) s; immersion 2: 21.34 (16.31) s; PIG: BHwater immersion 1: 24.66 (14.60) s; immersion 2: 44.25 (31.63) s]. The difference in maximum voluntary BHwater between immersion I and 2 in the PIG averaged 19.59 s, equating to an 80% increase following psychological intervention. Conclusion: Psychological influences may account for a significant amount of the variability in the respiratory responses during CWI, and may be a key factor in determining the chances of survival following accidental immersion.