Sleep Sounds: Which Type Works Best (Based on Research)

Over 3 million hours of sleep sounds are streamed on Spotify every day. But most people pick a random "sleep playlist" without knowing which sounds actually help, which might hurt, and which are just noise (literally). After reviewing the research, here's what the evidence says about every major sleep sound type, the risks most guides skip, and a clear protocol for using them.

The Masking Effect

The main reason sleep sounds help is simple: they cover up disruptive noises. A 2021 study found that background noise reduced nighttime awakenings in people living in high-noise environments. If you're in a noisy apartment, near a busy road, or sharing walls with loud neighbors, a consistent sound smooths out the sharp spikes that wake you.

Here's what most people miss: masking works by filling your auditory environment with predictable sound. Your brain can safely ignore something constant. It can't ignore something sudden. A car alarm at 2 AM cuts through silence. The same alarm is much harder to detect over a consistent background of rain or white noise.

But masking has limits. If your environment is already quiet, adding sound doesn't improve sleep. It may actually make it slightly worse. The 2026 Penn Medicine study (more on this below) found that even moderate-volume broadband noise reduced REM sleep in a controlled lab setting. So the benefit depends entirely on your noise situation.

The Relaxation Response

Some sleep sounds go beyond masking. Nature sounds in particular activate the parasympathetic nervous system, your body's rest-and-digest mode.

A 2017 fMRI study at Brighton and Sussex Medical School tested natural vs. artificial sounds on 17 adults. Natural sounds increased parasympathetic activity and shifted the brain's default mode network toward outward-focused attention. Artificial sounds did the opposite, pushing the brain toward the inward-focused rumination pattern associated with anxiety and depression.

I found this distinction useful: nature sounds aren't just pleasant. They actively signal safety to your nervous system. Artificial tones and pure synthetic noise don't trigger the same response. If relaxation is your goal (not just masking), the sound type matters.

White Noise

What it is: Equal energy across all audible frequencies (20-20,000 Hz). Sounds like TV static or a fan on high.

Research strength: The most studied sleep sound. A 2021 study in high-noise NYC environments found it helped participants fall asleep faster. Multiple hospital studies show it reduces nighttime awakenings. However, a systematic review in Sleep Medicine Reviews concluded that overall evidence for white noise improving sleep was "little beneficial effect."

Best for: Maximum masking power, especially against high-frequency sounds (voices, electronics, traffic). Parents of newborns have used it for decades.

Downsides: Many people find it harsh and fatiguing, especially at higher volumes. The 2026 Basner study warns that all broadband noise (including white) may reduce REM sleep.

My take: White noise is the blunt instrument of sleep sounds. It works for masking, but it's not pleasant. If you need serious noise blocking, it delivers. If comfort matters, look elsewhere.

Pink Noise

What it is: More energy in lower frequencies, less in higher ones. Sounds like steady rain or wind.

Research strength: A 2017 Northwestern study found precisely timed pink noise bursts enhanced deep sleep and tripled memory recall in older adults. But the 2026 Penn Medicine study found continuous pink noise at 50 dB reduced REM sleep by about 19 minutes per night across 7 nights.

Best for: People who want natural-sounding masking. People with ADHD may benefit for focus (OHSU meta-analysis found small but significant improvements).

Downsides: The REM reduction concern is real. The deep sleep benefits came from a very specific protocol (timed bursts synchronized to brain waves), not from playing continuous pink noise through a speaker.

My take: Pink noise sits in an awkward spot. The old research made it look great for sleep. The new research complicates that picture. I'd use it with a timer (30-60 minutes), not all night. For more details, see the full guide on pink noise for sleep and focus.

Brown Noise

What it is: Heavy emphasis on very low frequencies. Sounds like deep rumbling thunder or a waterfall up close.

Research strength: Weak. Brown noise has very few controlled sleep studies. Its popularity is driven by anecdotal reports, especially from the ADHD community on social media.

Best for: People who find white and pink noise too "hissy." The deep bass can feel immersive and calming. Some people describe it as "wrapping" sound.

Downsides: No strong sleep evidence. The bass-heavy profile may not mask higher-frequency sounds effectively. Same REM concerns as other broadband noise types.

My take: Brown noise is the most divisive. People either love it or find it oppressive. If you've tried white and pink noise and didn't like either, brown noise is worth a shot. But don't expect research to back up the hype. For a full breakdown, see the brown noise guide.

Nature Sounds (Rain, Ocean, Forest)

What it is: Recordings of natural environments. Can include rain, ocean waves, birdsong, wind, or forest ambience.

Research strength: Moderate and specific. The 2017 Brighton & Sussex fMRI study showed parasympathetic activation. A PNAS meta-analysis found water-based sounds (rain, streams) had the greatest positive health outcomes among all nature sound types. A hospital study found nature sounds improved sleep quality over 5 nights compared to no sound.

Best for: Stress reduction, anxiety management, creating a calming pre-sleep routine. People who find synthetic noise unpleasant.

Downsides: Quality varies wildly. Many YouTube videos and apps use cheap loops with audible repeat points. Thunderstorm recordings can include sudden volume spikes that trigger arousal. The REM concern from the Basner study applies to any continuous sound during sleep.

My take: Rain sounds are my top recommendation for most people who want a sleep sound. They're natural, comfortable, and have the parasympathetic benefit that synthetic noise doesn't. Use a timer and keep the volume low. Avoid thunderstorm tracks for sleep (save those for focus).

Music

What it is: Usually "relaxation" or "sedative" music at 60-80 beats per minute.

Research strength: A 2021 meta-analysis of 22 studies found that music improved self-reported sleep quality. Another meta-analysis found sedative music helped older adults sleep. The evidence is decent for subjective improvement but weaker for objective sleep measures.

Best for: People who find noise types boring or anxiety-inducing. The familiarity and emotional content of music can be calming in a way that pure noise isn't.

Downsides: Lyrics can be stimulating. Tempo changes can disrupt relaxation. Personal taste matters enormously. What calms one person irritates another.

My take: If you sleep well with music, keep doing it. The research supports it, especially slow instrumentals in the 60-80 BPM range. But it's a personal preference tool, not a universal protocol.

ASMR

What it is: Autonomous Sensory Meridian Response. Whispering, tapping, crinkling, and other "trigger" sounds designed to produce a tingling relaxation sensation.

Research strength: A survey of 475 ASMR users found 82% used it for sleep. A 2022 study showed it reduced stress and anxiety in university students. But the research is very thin, mostly self-reported, and no controlled sleep studies exist.

Best for: People who experience the ASMR "tingle" response (not everyone does). Can be deeply relaxing for those who respond to it.

Downsides: Very divisive. If you don't experience ASMR, the sounds can be irritating or even anxiety-provoking. Content quality varies wildly. Most ASMR videos are too long and inconsistent for a reliable sleep tool.

My take: ASMR is a niche tool that works brilliantly for the right person and annoys everyone else. Try it once. If you feel the tingling response, explore further. If not, move on.

Binaural Beats

What it is: Two slightly different frequencies played in each ear create a perceived "beat" frequency. Delta frequencies (0.5-4 Hz) target deep sleep.

Research strength: Mixed. A 2024 study in Scientific Reports found some sleep benefits. But most studies are small, and the effect depends on using headphones (which many people find uncomfortable for sleep).

Best for: People comfortable sleeping in headphones or earbuds who want targeted brainwave effects.

Downsides: Requires headphones (one frequency per ear), which limits comfort. Results are inconsistent across studies. The mechanism (brainwave entrainment) is debated.

My take: The theory is interesting but the practical limitations are real. I wouldn't recommend binaural beats as a first choice for sleep. Try simpler approaches first.

I've referenced this throughout, but let me lay out the full picture because it changes how we should think about sleep sounds.

Dr. Mathias Basner at the University of Pennsylvania tested broadband noise at 50 dB over 7 nights with 25 adults. The headline finding: pink noise reduced REM sleep by about 19 minutes per night. Combined with environmental noise, it increased wakefulness by 15 minutes.

Dr. Basner stated: "REM sleep is important for memory consolidation, emotional regulation and brain development, so our findings suggest that playing pink noise and other types of broadband noise during sleep could be harmful, especially for children whose brains are still developing."

What this means practically:

1. Don't play sounds all night. Use a 30-60 minute timer for sleep onset, then let silence take over.
2. Keep volume under 50 dB. The study used 50 dB and still saw effects. Lower is better.
3. Be extra cautious with children. Developing brains need REM. Don't use noise machines in infant/toddler rooms all night.
4. Consider earplugs. The same study found earplugs more effective at protecting sleep from noise than playing masking sounds.

This doesn't mean sleep sounds are useless. It means the old approach of "just play rain sounds all night" is outdated. Use them strategically, not as a default.

Here's the decision framework I'd use:

If your main problem is environmental noise: Start with rain sounds on a 30-60 minute timer. If that's not enough masking, try white noise. If you want to avoid all risk, use earplugs.

If your main problem is a racing mind: Sound alone won't fix this. You need active nervous system regulation. A guided NSDR protocol with low-volume rain sounds in the background targets both the noise issue and the internal activation.

If you have ADHD and struggle with sleep: Pink noise may help with focus during the day and sleep onset at night. Use a timer and keep volume low.

If you just can't wind down: Don't reach for sound first. Ask whether your pre-sleep routine is the real issue. Screen time, caffeine timing, and inconsistent schedules cause more sleep problems than noise does. If you've addressed those and still struggle, try a 10-minute NSDR session to actively downshift your nervous system before bed.

Sleep sounds are passive tools. They change your sound environment, but they don't actively shift your body from a stressed state to a rest state.

That shift matters. If you're lying in bed with rain sounds playing but your mind is racing through tomorrow's tasks, the rain is doing almost nothing for you. You need an active intervention that guides your nervous system into parasympathetic mode.

NSDR (Non-Sleep Deep Rest) does this through structured body scans, guided breathing, and intentional relaxation protocols. It's not meditation. It's a protocol that gives your nervous system a clear signal to downshift.

The takeaway is: use sleep sounds for what they're good at (masking, mild relaxation). But if you need more than background noise to sleep, explore NSDR guided tracks for a structured approach. Many people find that 10 minutes of active regulation beats hours of passive sound.

What is the best sleep sound overall?

For most people, steady rain sounds on a 30-60 minute timer at under 50 dB. Rain provides natural masking, triggers the parasympathetic response, and most people find it comfortable. If you need stronger masking, try white noise. If comfort matters more, try brown noise.

Are sleep sounds safe for babies?

Use with caution. The American Academy of Pediatrics found infant noise machines can exceed safe volume levels. Keep devices across the room (at least 7 feet), use the lowest volume possible, and avoid running sounds all night. The 2026 Basner study specifically warns about broadband noise and developing brains that need more REM sleep.

Should I play sleep sounds all night?

No. Based on the 2026 Penn Medicine study, continuous noise may reduce REM sleep. Use a timer (30-60 minutes) to cover the sleep-onset period, then let your brain sleep in quiet. This is the approach recommended by Dr. Rafael Pelayo at Stanford.

Can sleep sounds replace medication for insomnia?

Sleep sounds are a tool, not a treatment. They can help with noise-related sleep disruption but don't address the underlying causes of clinical insomnia. If you have chronic sleep problems, work with a healthcare provider. Cognitive behavioral therapy for insomnia (CBT-I) has much stronger evidence than any sleep sound.

How long does it take for sleep sounds to work?

Most people notice a difference in sleep onset within the first few nights if noise disruption is their main issue. Give it 3-5 nights before deciding. Your brain needs time to associate the sound with sleep. If you're still not sleeping better after a week, the sound isn't your problem.