March 26, 2026
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People may sleep deeply while having intense, immersive dreams, a new study suggests. That challenges prior beliefs that deep sleep is linked to periods of slow brain wave activity.
Waking up from a vivid, emotionally-charged dream can feel disorienting and sometimes disturbing.
But new research shows that intense dreams actually may give people the sense of having had more restorative sleep.
Scientists previously believed that the feeling of having slept deeply was associated with periods of slow brain wave activity. But the new study, published Tuesday, found instead that people reported having slept deeply – even during periods of "wake-like" brain wave activity – if they were aware of dreaming.
This type of study is difficult to conduct, because it requires "serial awakening," or waking up people repeatedly throughout the course of several nights and asking them to describe their experiences, the researchers said.
The study involved 44 healthy adults who had small electrodes attached to their heads to record brain activity. The researchers repeatedly awoke the people in the study over four nights to collect data.
People felt they had slept deepest when they awoke from a vivid dream they recalled or "from states lacking any conscious experience," the study said. After periods of sleep when people experienced a "mere feeling or presence or awareness of time passing," they reported shallower sleep.
"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," the study's authors said in a press release.
"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."
