The LF/HF ratio and AHI were both s

The LF/HF ratio and AHI were both significantly higher in light as compared to dark. Before sleep onset, the coefficient of variation (CV) for breath-to-breath tidal volume representing breathing irregularity tended to be higher in light than in dark environment. The CV values for tidal volume after sleep onset were significantly decreased compared with before sleep onset in both sleep environments. Mutual information of the ventilatory pattern was significantly lower before sleep onset than after sleep onset, only in the light environment.