"Sounds for Sleep" Having the Opposite Effect? Shocking News for Rain Sound and White Noise Fans: Study Suggests "REM Sleep May Be Reduced"

"Sounds for Sleep" Having the Opposite Effect? Shocking News for Rain Sound and White Noise Fans: Study Suggests "REM Sleep May Be Reduced"

"I feel uneasy without silence," "I can't fall asleep without the sound of rain or a soft noise"—for such people, sleep sound apps and videos are the "modern lullabies." However, these "allies for falling asleep" might be cutting out important stages necessary for sleep recovery. This suggestion comes from the latest research that precisely measured the impact of "pink noise (a type of broadband noise)" played during sleep.


The Identity of "Chii...": Differences Between White, Pink, and Brown Noise

Generally, sleep sounds referred to as "noise" include white noise, pink noise, and brown (or brown) noise. Broadly speaking, white noise is bright and shushing, pink noise leans slightly towards the lower frequencies, and many people feel it resembles the sound of rain. Apps and videos are marketed with contexts like "helps concentration," "puts babies to sleep," and "blocks out external noise," aiming to create a sense of security by "masking" everyday sounds.


However, it's important to note that "ease of falling asleep" and "quality of sleep" are not the same. Even if you fall asleep quickly, if your sleep is fragmented or if REM sleep, where dreams occur, is reduced, the sense of recovery the next day may decrease. The research in question focused precisely on this "content."


What the Research Did: 7-Night Experiment with Aircraft Noise, Pink Noise, and Earplugs

The research team measured polysomnography (brain waves, eye movements, muscle activity, etc.) in a sleep lab over seven nights with 25 healthy adults. There were multiple conditions: (1) a quiet control night, (2) intermittent environmental noise (event sounds simulating aircraft noise), (3) pink noise (40 or 50 dBA), (4) environmental noise + pink noise, (5) earplugs, (6) environmental noise + earplugs. In the morning, cognitive tests, cardiovascular indicators, hearing, and subjective evaluations were also conducted.


The point is that the realistic idea of "can you sleep if you cover noisy environments with pink noise?" was rigorously tested in a laboratory setting. In other words, they quantified a situation close to the promotional claims of apps.


Results: Pink Noise Reduces REM Sleep, and Combinations "Worsen"

In conclusion, pink noise was not a universal remedy.

  • Environmental noise (aircraft noise) reduced deep sleep (N3: so-called "deep sleep").

  • On the other hand, pink noise reduced REM sleep.

  • Furthermore, when pink noise was combined with environmental noise, the overall sleep structure worsened, and it was deemed unsuccessful as a "countermeasure," according to the authors' evaluation.

  • Earplugs "almost" offset the impact of environmental noise (though effectiveness began to decline near maximum levels).


The subjective evaluations were also intriguing. While cognitive, cardiovascular, and hearing measures in the morning did not change significantly, sleep satisfaction, sleepiness, and mood worsened on nights with noise or pink noise.


In other words, "measuring shows sleep is disrupted, and the person feels 'something's off.'"


Why REM Sleep is Important: Dream Time is Also "Brain Maintenance"

REM sleep is considered a stage involved in memory consolidation and emotional regulation. Researchers emphasized concerns about the reduction of REM sleep itself, particularly its impact on children. Infants and young children are said to have a higher proportion of REM sleep than adults, suggesting that indiscriminate "habitual use of broadband noise" should be considered carefully.


What's Important Here: It's Not a Matter of "Immediate Out" from Tonight


But "Noise = Bad" Isn't the Conclusion: Context and Limitations of the Research

On social media, concerns quickly spread with reactions like "So, is white noise bad too?" and "I was playing it for my baby..." Meanwhile, there were also notable counterarguments like "I was saved by noise" and "Silence is impossible with noisy neighbors."


In fact, past research and explanations have pointed out the possibility that noise can cancel out disruptive sounds and aid sleep. However, studies showing effects may have different "playback methods." For example, methods like "closed-loop" sound stimulation that aligns with brainwave timing are different from simply playing noise all night, which is an important distinction.


This study is understood as a caution against "continuous playback of broadband noise," minimizing discrepancies.


SNS Reactions: Divided Opinions on the Gap Between "Experience" and "Measurement"

When the article spread, reactions were broadly divided into three types.


1) "I Knew It..." Those Who Found the Reason for Their Discomfort
In the health influencer and sleep improvement communities, there was an increase in posts quoting the study's key points, such as "felt lighter sleep with pink noise/increased wake-ups," as a warning against "habits believed by atmosphere."


2) "But It Helps Me" The Pragmatic Group
On the other hand, real sleep environments vary for each person, such as in apartment complexes, areas with heavy traffic, and family living noises. Voices speaking from experience, like "I feel anxious and can't sleep without silence" and "I wake up reacting to noises without fan or air conditioning sounds," are strong. Since sleep satisfaction influences behavior, resistance from this group is strong.


3) "I Used It for My Child..." The Uneasy Parenting Group
The most shaken were parents who use (or used) noise for putting babies to sleep. The researchers also raised concerns about "children having more REM sleep," concentrating SNS anxiety here.


However, it is necessary to calmly consider "volume," "playback time," and "alternatives." It's not a matter of zero or one hundred, but a discussion that can be translated into a design to reduce risks.


So What to Change from Tonight? A Realistic "Compromise"

The study indicated that "earplugs are surprisingly strong."
Before completely dismissing apps, the following "choices to minimize harm" are realistic.

  • Start with a Timer: Avoid continuous playback all night, limit it to a short time until falling asleep.

  • Lower the Volume: Keep it to the minimum necessary. If a small sound suffices, that's better.

  • Break Down the Purpose: Is it "calming anxiety" or "blocking disruptive noise"? If it's the latter, earplugs, soundproofing, or improving the bedroom environment may be effective.

  • Be Especially Careful with Children: Avoid habitual use, high volume, and long durations; consult a pediatrician or sleep specialist if concerned.


Ultimately, the right answer for sleep varies for each person. However, assumptions like "popular means safe" or "sounds like nature, so it's gentle on the brain" were shaken by this data. Noise "works for some but not only doesn't work for others, it can even detract." Understanding this, redesigning usage—this is likely the most practical takeaway from this research.


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