Development of periodic breathing in awake healthy individuals under controlled progressive hypoxia

The aim of this study was to better understand the ventilatory response to controlled progressive hypoxia in healthy individuals and identify factors influencing the development of periodic breathing under hypoxic conditions. The study was conducted in a hypoxia room at the Complementary Medical Centre in Genk, Belgium. Eighteen healthy participants were subjected to controlled progressive hypoxia, with oxygen levels ranging from 0.21 to 0.10. Oxygen saturation (SpO₂) was measured using a Nellcor® PM10N pulse oximeter, and carbon dioxide levels, including end-tidal carbon dioxide (EtCO₂), were monitored using a Philips LoFlo® sidestream device. Recorded data of SpO₂ sensor and capnography were analyzed whether sex, age, and Body Mass Index (BMI) were factors influencing the participants' ventilatory response to hypoxic conditions. RESULTS: showed that 22 % of the study participants developed periodic breathing, all of whom were men, particularly older individuals, with an average age of 40.0 ± 16.2 years (p = 0.026). There was a notable sex-specific response, with 100 % of periodic breathing cases being male (p = 0.078). Significant correlations were found within the periodic breathing group: BMI correlated with the SpO₂ value at the start of PB (R²=0.987, p = 0.013), the pulse rate at the start of periodic breathing (R²=-0.992, p = 0.008), and the EtCO₂ at the end of the first breath after the apneic phase (R²=0.908, p = 0.092). These findings indicate that sex, age, and BMI are critical factors in determining an individual's ventilatory response to hypoxic conditions. Periodic breathing developed exclusively in men, and the physiological state at the onset of periodic breathing, measured by the SpO₂ and pulse rate, was significantly correlated with BMI.