In which stage of sleep do most sleep disorders occur?

The most sleep disorders typically occur during Stage 2 non-REM sleep. This stage is characterized by sleep spindles and K-complexes, which are important for sleep stability and overall sleep architecture. During Stage 2, individuals are more easily aroused compared to deeper stages of sleep, which may contribute to the prevalence of certain sleep disorders manifesting here.

This stage plays a crucial role in consolidating memory and learning, and disturbances during this phase can lead to issues such as sleep apnea and other disruptions. Sleep disorders like insomnia and periodic limb movement disorder also commonly surface during this stage, as it represents a lighter level of sleep where the brain is still somewhat responsive to external stimuli, making it more susceptible to disturbances.

In contrast, other stages of sleep, such as REM and deeper stages of non-REM sleep (Stage 3), have different characteristics and are linked to other types of sleep disturbances, but Stage 2 is particularly notable for the frequency of sleep disorders occurring.