Development of a novel hypoxic training method using carbon dioxide. - Development of a novel hypoxic training method using carbon dioxide.

A comparison of polysomnography (PSG), heart rate variability analysis, and oxygen desaturation indices (ODI) for low-oxygen trials (15.4% O2) and low-oxygen, high-carbon dioxide trials (15.4% O2, 1500 ppm CO2) was conducted. No statistical significance was found among Stages N1, N2, N3, and R. The heart rate variability analysis showed no statistical significance among RR interval (RRi), high frequency (HF), and the ratio of low frequency to high frequency (LF/HF). There was no statistical significance among blood oxygen saturation (SpO2), ODI3, and ODI4. The concentration of carbon dioxide (1500 ppm) in the room did not have an adverse effect on the physiological response while sleeping in a low-oxygen environment.