Many people turn to sound machines or apps offering “pink noise” to help them fall asleep, believing these ambient sounds create a more restful environment. However, new research suggests this popular sleep aid may actually be detrimental to sleep quality, particularly by reducing the amount of restorative REM sleep. A study published , in the journal Sleep, found that while earplugs effectively protected sleep from disruptive noises like traffic, pink noise had the opposite effect.
The study, conducted by researchers at the University of Pennsylvania Perelman School of Medicine, observed 25 healthy adults between the ages of 21 and 41 in a sleep laboratory over seven consecutive nights. Participants, who reported not previously using noise to aid sleep and had no existing sleep disorders, were exposed to various conditions: aircraft noise, pink noise, a combination of aircraft noise and pink noise, and aircraft noise while wearing earplugs. Each morning, participants underwent tests and completed surveys to assess sleep quality, alertness, and overall health effects.
The findings revealed a significant reduction in REM sleep for those exposed to pink noise. “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 and who spend much more time in REM sleep than adults,” explained Mathias Basner, MD, PhD, professor of Sleep and Chronobiology in Psychiatry, and lead author of the study.
This is not the first indication that sound machines may not be the panacea for sleep problems they are often marketed as. A separate report, published , highlighted similar concerns, noting that pink noise can interfere with the most restorative stages of sleep. The research underscores the importance of understanding the different stages of sleep and how external factors can impact them.
During sleep, individuals cycle through periods of deep sleep and REM sleep. Deep sleep is crucial for physical restoration, memory consolidation, and clearing toxins from the brain. REM (Rapid Eye Movement) sleep, often associated with dreaming, plays a vital role in emotional regulation, motor skill development, and brain maturation. Disrupting either stage can have negative consequences for overall health and well-being.
The University of Pennsylvania study specifically examined the impact of these sounds in the context of aircraft noise, a common environmental disturbance. Interestingly, the combination of aircraft noise and pink noise resulted in even poorer sleep quality than exposure to aircraft noise alone. This suggests that adding pink noise in an attempt to mask disruptive sounds can actually exacerbate the problem.
In contrast, earplugs proved to be a simple and effective solution for protecting sleep from traffic noise. The study demonstrated that earplugs were significantly more effective at preserving sleep quality compared to pink noise, offering a more reliable way to mitigate the impact of external disturbances.
The implications of these findings are particularly relevant for children. Because children spend a greater proportion of their sleep time in REM sleep compared to adults, the potential for harm from pink noise exposure is heightened. The researchers caution that the widespread use of sound machines and sleep apps relying on continuous background noise could be inadvertently hindering brain development and emotional regulation in young children.
The growing popularity of sound machines and sleep apps has led many to believe that ambient noise is a reliable sleep aid. However, this research challenges that assumption, suggesting that these devices may be doing more harm than good. While the appeal of masking disruptive sounds is understandable, the study highlights the importance of considering the potential impact on sleep architecture and restorative sleep stages.
The findings from the University of Pennsylvania study add to a growing body of evidence questioning the efficacy of certain sound-based sleep aids. While further research is needed to fully understand the long-term effects of pink noise exposure, the current evidence suggests that simple earplugs may be a more effective and safer option for protecting sleep from environmental noise. Individuals struggling with sleep disturbances should consult with a healthcare professional to determine the most appropriate course of action.
