You know the vibe: turn on a sound machine, drift off, wake up “okay.” But new research suggests the type of sound you use may matter more than we thought.
Researchers at Penn Medicine tested common sleep setups and found that pink noise (a popular “sleep sound”) reduced REM sleep—the stage tied to emotional processing and memory.
How they tested it
Participants slept under different conditions, including:
- Environmental noise (intermittent, like aircraft/traffic-style noise)
- Pink noise (steady “masking” sound)
- Pink noise + environmental noise
- Environmental noise + earplugs
What changed in sleep
- Pink noise was linked to less REM sleep.
- Combining pink noise with intermittent noise worsened sleep recovery overall.
- Earplugs were more effective at protecting sleep from intermittent noise than adding more noise.
Try this tonight (3-night reset)
- Night 1–3: Replace the sound machine with earplugs (or improved noise-blocking like door draft seals).
- If you keep the sound machine: lower volume and place it farther from the bed.
If your mornings feel calmer and your brain feels less “static,” you’ve got your answer.
Quick reality check
This is a controlled lab study with a specific setup, so it’s not a universal “ban.” But it’s a strong reminder: sometimes the best sleep upgrade is less input, not more.
