Progressive changes of oxygenation, diving response, and involuntary breathing movements during repeated apneas

This study investigated whether trained freedivers (n=21) were capable of sustaining a 1:1 apnea-to-recovery ratio without progressive arterial or cerebral oxygen desaturation in a laboratory setting. As part of the study, participants underwent slow vital capacity testing, which was performed in the standing position using a Vitalograph COMPACT spirometer.