Manipulating the perception of time affects voluntary breath-holding duration

In this study, we examined how time perception, a psychological factor, impacts the physiological response to prolonged, voluntary breath holding. Participants (n = 26) held their breath while watching a distorted timer that made it appear as though time was moving up to 40% faster or slower than real time. We monitored total breath-holding duration under different time manipulation conditions as well as the onset of involuntary breathing movements. This physiological breaking point marks the end of the "easy-going" phase of apnea and the start of the "struggle" phase. Based on prior work showing that psychological factors, such as attention and motivation, can influence the length of the struggle phase, we hypothesized that manipulating the perception of time would affect overall breath-holding duration by changing the duration of the struggle phase, but not the easy-going phase. We found that time perception can be successfully manipulated using a distorted timekeeper, and total breath-holding duration correlated with perceived time, not actual time. Contrary to our hypothesis, this effect was attributable to changes in the onset of the physiological breaking point, not changes in the length of the struggle phase. These results demonstrate that unconscious psychological factors and cognitive processes can significantly influence fundamental physiological processes.