Scientists continue to investigate how different stages of sleep contribute to rest, memory and learning, though the precise role of each phase remains unclear. Brain activity recorded through electroencephalograms allows researchers to distinguish these stages, yet their individual functions are still being examined.
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A recent study published in PLOS Biology focused on non-rapid-eye-movement stage 2 (NREM2), which accounts for roughly half of total sleep. Through repeated awakenings in a laboratory setting, participants reported their experiences, revealing that immersive dreams were often linked to a strong sensation of having slept deeply, even when brain activity suggested a lighter state.
Researchers found that people sometimes felt deeply asleep both when brain activity indicated unconsciousness and when they experienced vivid, immersive dreams. This suggests that the perception of sleep depth may not always align with measurable brain states, raising questions about how dreaming influences subjective rest.
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Experts note that the findings require further investigation, particularly regarding how dreams affect overall sleep quality. The study highlights the complexity of sleep, suggesting that a sense of disconnection from the external world—whether through deep unconsciousness or vivid dreaming—may shape how restorative sleep feels.
