Can calming sleep noises actually disrupt your dreams?

It turns out that a glass of apple juice before bed isn’t the only thing that can sabotage your dreams. A study by scientists at the University of Pennsylvania has found that pink noise may lower the amount of time you spend in REM sleep, the stage associated with vivid dreams.

The researchers observed 25 healthy adults between the ages of 21 to 41 to see how certain noises affected their sleep. Over the course of a week, the participants were exposed each night to just aircraft noise, just pink noise (typically crashing waves or other gentle nature sounds), aircraft noise and pink noise, and aircraft noise while wearing earplugs, with no noise as the control condition.

Participants unsurprisingly experienced an average of 23 fewer minutes of N3 sleep, the deepest stage, while listening to aircraft noise alone. But they also experienced a 19-minute reduction in REM sleep while listening to pink noise alone. However, the results for pink noise were “not all bad,” according to lead study author Mathias Basner. “Pink noise helped a little bit improving deep sleep and reducing sleep fragmentation (i.e., waking up to environmental noise),” he said. “Therefore, it is still hard to say what the long-term consequences would be, especially since we don’t have data on long-term use.”