Background: Sudden unexpected death in epilepsy (SUDEP) is a major cause of epilepsy-related mortality, particularly among individuals with chronic and drug-resistant epilepsy. Although generalized tonic-clonic seizures are the strongest established risk factor, the predominance of SUDEP during sleep suggests that sleep-related physiological disturbances may contribute importantly to its pathogenesis.

Objective: To review contemporary evidence on the relationship between sleep disturbances and SUDEP, emphasizing sleep physiology, cardiorespiratory dysfunction, autonomic instability, neurocardiology mechanisms, and potentially modifiable risk factors.

Methods: A narrative review of the literature was conducted using PubMed, Web of Science, Scopus, Embase, and Google Scholar, with primary emphasis on studies published from January 2020 through March 2026. Earlier landmark studies were included when necessary to establish key definitions, epidemiological observations, and mechanistic concepts. Relevant clinical studies, systematic reviews, meta-analyses, consensus statements, practice guidelines, and clinically relevant translational studies were evaluated.

Results: Evidence indicates that sleep disturbances are common in epilepsy and may increase SUDEP vulnerability through interacting mechanisms involving nocturnal seizures, intermittent hypoxemia, impaired arousal, autonomic dysfunction, cardiac arrhythmogenesis, postictal generalized EEG suppression, and brainstem respiratory dysregulation. Obstructive sleep apnea is particularly prevalent and potentially modifiable. Emerging evidence also supports a brain–heart–lung axis linking recurrent seizures with progressive cardiorespiratory and autonomic abnormalities. However, direct evidence that treatment of sleep disorders reduces SUDEP incidence remains limited.