Researchers led by Guilio Bernardi at the IMT School for Advanced Studies Lucca in Italy announced on March 24 that immersive dreaming during sleep may play a key role in how rested people feel, regardless of actual brain wave activity. The findings were published in PLOS Biology.
The study is significant because it challenges the traditional belief that only slow-wave brain activity determines how deeply someone feels they have slept. Instead, the research suggests that experiencing vivid and emotionally intense dreams can lead to a greater sense of deep sleep.
To conduct the study, researchers analyzed EEG recordings from 44 adults who were awakened multiple times during non-REM sleep over four nights. They found that while shifts from faster to slower brain waves are generally linked to feeling well-rested, this connection was weaker when participants reported having had a dream—even if they could not recall its content. The study found that vivid and bizarre dreams were associated with deeper perceived sleep, while more abstract or self-aware dreams made people feel their sleep was shallower.
These results suggest that perceptually immersive dreaming may help individuals feel well-rested even if they do not remember their dreams. "We already know that dreaming extends beyond REM sleep and occupies a large portion of the night, yet its function remains unclear. Our study suggests that dreams may help shape how we experience sleep by immersing us in an internal world that keeps us disconnected from the external environment," said the authors.
The researchers also said, "Understanding how dreams contribute to the feeling of deep sleep opens new perspectives on sleep health and mental well-being. Alterations in dreaming - for example, a reduction in the richness or frequency of dreams - could influence how people perceive their sleep depth or duration, and may contribute to dissatisfaction with sleep quality."
They added, "This kind of research is extraordinarily demanding. Serial awakening studies require waking participants repeatedly across multiple nights and collecting detailed reports each time. It was only possible thanks to the dedication, resilience, and coordination of an exceptional team of researchers."
