Nocturnal hypoxia moderates the relationship between rapid eye movement sleep and anxiety.

Objective: Sleep problems, especially rapid eye movement sleep disturbances, are associated with various neurological and psychological disorders. Given the potential of nocturnal hypoxia to induce psychological symptoms, we investigated its moderating effect on the relationship between sleep variables and psychological symptoms among individuals with sleep disturbances.

Methods: A total of 160 participants who complained of sleep problems were enrolled, and their hypoxic and sleep indices were recorded using overnight polysomnography. The psychological status of all participants was further assessed using Symptom Checklist-90-R (SCL-90-R, Chinese version). Hierarchical regression analyses were employed to examine the influence of hypoxic indices and sleep indices, and the interaction of these variables on psychological symptoms. Simple slope analyses were used to probe significant interactions.

Results: Hierarchical regression analyses indicated that the cumulative duration of nocturnal hypoxia (SpO₂ < 95%) moderated the relationship between the percentage of rapid eye movement sleep (RT%) and psychological symptoms (somatization, obsessive compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, and psychoticism). To account for the increased risk of Type I errors due to multiple statistical tests, we applied False Discovery Rate correction. After applying the FDR correction, the p-value for the cumulative duration of nocturnal hypoxia (SpO₂ < 95%) in moderating the relationship between RT% and anxiety remained significant (β = 0.312, △ F = 16.586, p < 0.01, 95% confidence interval [0.009, 0.025]).

Conclusion: Our study demonstrates that nocturnal hypoxia, particularly the cumulative duration of hypoxia (SpO₂ < 95%), moderates the association between RT% and anxiety symptoms. These findings indicate a potential interaction between rapid eye movement sleep and nocturnal hypoxia in relation to psychological symptoms. Further research is warranted to clarify the underlying mechanisms.