Vivid Dreams May Make Sleep Feel More Restful

A study published March 26, 2026, in the journal PLOS Biology found that vivid, immersive dreams during the NREM2 sleep phase - a non-REM stage not traditionally associated with dreaming - were linked to participants reporting deeper and more refreshing sleep, even when their brain activity during that period was elevated, according to ScienceDaily. The research was conducted by scientists at the IMT School for Advanced Studies Lucca in Italy and challenges a long-held assumption: that the brain must be quiet for sleep to feel restorative.

Over four nights, 44 healthy adult participants were awakened more than 1,000 times in a sleep laboratory and asked to describe what they had been experiencing immediately before waking. They also rated how deeply they felt they had been sleeping.

What Participants Reported

The data showed a consistent pattern. Participants reported the deepest, most restorative sleep not only when they experienced no conscious activity at all, but also after vivid and immersive dream experiences. Shallow, unrefreshing sleep, by contrast, was linked to fragmented or minimal mental activity - vague sensations of presence without any clear dream content, according to ScienceDaily.

The finding inverts the conventional picture. In the traditional model, brain activity during sleep signals lighter, less restorative rest. But for participants whose dreams were highly immersive, elevated brain activity during NREM2 sleep did not translate into a sense of poor rest - it translated into the opposite. “Not all mental activity during sleep feels the same: the quality of the experience, especially how immersive it is, appears to be crucial,” senior author and neuroscience professor Giulio Bernardi said, as reported by ScienceDaily.

A Counterintuitive Pattern Across the Night

The researchers identified a second unexpected result in the data. Across each night, the physiological markers of sleep pressure - the body’s biological drive to sleep - decreased over time, as expected. What the researchers did not expect was that participants continued to report feeling that their sleep was getting deeper as the night progressed, not shallower.

That subjective deepening tracked closely with an increase in how immersive participants’ dreams became over the course of the night, according to ScienceDaily. The researchers suggest that dream experiences may act as a buffer - helping maintain the subjective feeling of deep, restful sleep even as the body’s biological need for sleep naturally declines in the later hours.

The “Guardian of Sleep” Hypothesis

The findings connect to a longstanding theoretical idea in sleep research - one that dates to classical psychoanalysis - that dreams may serve a protective function, acting as guardians of sleep by keeping the sleeper from waking. The IMT study provides empirical support for a version of that hypothesis, suggesting that immersive dream experiences help maintain a sense of separation from the external environment, which is a defining feature of restorative sleep.

“If dreams help sustain the feeling of deep sleep, then alterations in dreaming could partly explain why some people feel they sleep poorly even when standard objective sleep indices appear normal,” Bernardi said, as quoted by ScienceDaily. That framing has direct implications for people who report chronic feelings of poor sleep despite normal clinical measurements - a category that has been difficult to explain through conventional sleep science.

What Comes Next

The researchers described the study as an early step rather than a definitive conclusion. Brain activity monitoring was conducted using high-density EEG, and the study was carried out as part of a collaboration among the IMT School, Scuola Superiore Sant’Anna in Pisa, and Fondazione Gabriele Monasterio. The IMT group has established a new sleep laboratory combining neuroscientific and medical research aimed at better understanding how brain and body dynamics interact across the sleep-wake cycle. Further research will be needed to determine whether altering the quality of dream experiences can reliably influence how restorative sleep feels - and whether that has any measurable effect on waking cognitive performance or longer-term health outcomes.

References: Vivid dreams may be the secret to deeper, more restful sleep | Ar Aa1Zly6N