SNOO's White Noise

SNOO provides continuous sound to reduce infant crying and improve infant sleep. And improved sleep supports the development of a healthy brain (Donnici, C. et al. J Affective Disorders 339 (2023): 118-126). Reducing infant waking/fussing may be additionally helpful because persistent crying has been associated with parent stress/anxiety, postpartum depression, child abuse, etc.

For context, the sound of rain is about 50 dB, the sound in a NICU averages ~60 dB (and many dB higher inside incubators), a normal conversation is 60-65 dB, the sound in a car is 65-75 dB, womb sound is 75-92 dB, hair driers are 90 dB, and a baby’s cry reaches 100-120 dB (somewhere between a rock concert and a jet taking off) and since it comes from the child’s throat, it’s just inches from the ear.  There are no studies that show that a sound machine can negatively impact a child’s hearing. Similarly, there is no published evidence that supports the belief that infants need to avoid sound over 50 dB.

Note: Infant caregivers around the world routinely shush babies softly (60-70 dB) to help them fall asleep and shush more loudly – and high pitched – when soothing crying infants. The impact of a sound on the ear increases 10x with every increase of 10 decibels (dB). For example, 85 dB appears to be numerically very close to 70 dB, but 85 dB noise is actually 50 times harsher and more impactful on hearing. In other words, a mom singing lullabies all night (essentially 70 dB sound) or playing 70 dB white noise all night would have a dramatically different impact on the ear than constant, workplace “hair drier” level 85+ dB noise for 8 hours/day 5 days/week. 

SNOO’s baseline (all-night) sound mimics the womb’s 24/7 soothing rumble but instead of 75-92 dB, it’s a much lower ~63 dB, similar to a parent’s normal conversation. By way of comparison, 70 dB Is the level of a mom softly shushing or singing a lullaby to her baby. If desired, the SNOO app can be used to lower the baseline sound to ~55 dB. The sound does increase when babies cry because increasing sound and motion are commonly used infant care practices to calm fussing and lull babies to sleep (used by experienced baby calmers).

In 2023, the American Academy of Pediatrics (AAP) released a review of children and sound. That article mentioned a sound machine study which found a few of the 14 machines studied exceeded the maximum sound level allowed for working adults (85 dB for 8 hours). The sound machines only exceeded that level if they were: played all night, turned all the way to the max sound, and placed <1’ from the child’s head. Note: The AAP reported that white noise has been shown to improve infant sleep and decrease crying. The AAP review offers 15 specific recommendations, but they did not advise banning infant sound machines.

SNOO motion/sound also helps sleep trains babies and SNOO plus its SNOO’s special swaddle is the only FDA de novo authorized positioner proven to keep babies safely on the back all night. Rolling to the stomach has been associated with a higher risk of infant death. Happiest Baby surveys have shown that SNOO users are much less likely to bed share, place their baby to sleep on the stomach, or in SNOO with bulky bedding that can be a suffocation risk. Finally, studies have demonstrated that although swaddling enhances sleep it has the added benefit of encouraging arousability (responsive to stimuli) in the infant’s brain.

SOURCES: [1] Franco P, et al. Increased cardiac autonomic responses to auditory challenges in swaddled infants. Sleep 2004;27;1527-32. [2] Franco P, et al. Influence of swaddling on sleep and arousal characteristics of healthy infants. Peds. 2005;115:1307-11