"Are Sound Machines and White Noise Really Effective for Better Sleep?"

If you take a look any baby registry these days, you will likely find a sound machine of some kind being requested. Sound machines have been used for decades to enhance sleep in both children, and adults. But recently, researchers have been starting to see if white noise actually makes a difference in someone's quality of sleep, and if white noise could even be harmful to our brain or development with prolonged use.

So what are the potential risks of using a sound machine or white noise?

We risk damaging our hearing. With prolonged use, any sound, even if its white noise, can be damaging to our ears. The CDC states that anything over 70 dB for 8+ hours at a time can possibly harm our hearing. For context, the CDC lists normal human conversation at approximately 60 dB.

We might not be allowing our brain to truly "rest". The whole point of sleep is for our body to rest and for our brain to recover and process/store information (among other things)! Even though we are asleep, our brain is still at work doing the above things. If we are giving our brain a constant stimuli to process, there is concern that we will have a decreased quality of sleep that makes us feel unrested in the morning, or harm our ability to develop new skills, memories, etc.

And finally, there is concern that using a sound machine, or white noise creates a "sleep crutch" or sleep association that cannot be broken. That means that an individual must be listening to the noise in order to sleep. This can lead to difficulty napping/sleeping in different environments or places.

If all of the above is true, why do so many people still use sound machines? Why are they still being recommended? What are the benefits?

Specifically for babies, sound machines can mimic some of the noises heard in the womb such as the "whoosh" of their mother's heartbeat. This can be very soothing and calming to the child. It has been shown in the research, that because of this, using a sound machine can shorten the amount of time it takes a baby to fall asleep. For children and adults, sound machines can work to block out household noises such as doors being opened and cabinets being closed, or cars driving by outside. There was one study that exposed participants to common hospital noises while they slept both with and without white noise. They found that those exposed to hospital noises with white noise had fewer arousals compared to those that were not exposed to white noise.

What about all of the stimuli that white noise provides the brain to process throughout the night? I have several thoughts on this. My first is that sound machines play a predictable and repeated pattern of sound. This is important to make note of because regardless if you use a sound machine or not, your brain will most likely need to process some sort of extra stimuli throughout the night. A stimuli that is low in volume, predictable, and repeating will require less attention from your brain. Your brain will start to "tune it out". Stimuli that occurs at variable times and volumes while sleeping will require more attention from the brain to decide what the noise is, does it need to be filtered out, can we stay asleep, etc. Most household and environmental stimuli will fall into the latter group of stimuli. Remember, these stimuli tend to get tuned out by the sound machine.

Please note that falling asleep to music or the television also falls into the "unpredictable stimuli" category and is not advised.

We can also choose different types of sounds to listen to on most sound machines. Each sound, or type of noise, has a different frequency to it. While white noise, or the "TV static", is very common, it has a pretty high frequency of sound waves. We can choose to pick other noises that have lower frequencies. Try looking for either brown or red noises to fall asleep to. These sounds will be deeper in tone and sound almost like a gentle "roar" or "wave" instead of like static. This is another way to decrease extra stimuli that the brain needs to process.

Using a sound machine can also create a sleep association. Wait, wasn't this listed as a possible concern? Yes, it was. However, in the sleep consulting world, we break down sleep associations into positive and negative associations. Positive sleep associations help provide cues to your child so they know when it's time to fall asleep. Examples of this can include: putting on a sleep sack, reading a book in their room with their pajamas on, or turning on a sound machine. They start to know that when the sound machine turns on, it means it is time to fall asleep. If they wake up in the middle of the night and get confused on what time it is, they will hear the sound machine running and be more likely to resettle themselves back to sleep independently. These sleep associations actually help create healthy sleep hygiene habits.

The bottom line?

When used correctly at a volume no greater than 50 dB, placed at least 3.5 feet away from a sleep surface, (American Association of Pediatrics guidelines), sound machines should be safe to use, and could provide you or your child more restful sleep. While this is still a "hot topic" that is being researched, currently there is not enough good evidence to support long-term complications in development unless the sound machine is being used otherwise.

In short, you keep that sound machine on your registry mama!

Do you have questions on how else you can support your child's sleep habits? Book your free 15-minute Discovery Call by filling out our form on the "Contact" page of this website.

Resources

Yoon H, Baek HJ. External Auditory Stimulation as a Non-Pharmacological Sleep Aid. Sensors (Basel). 2022 Feb 7;22(3):1264. doi: 10.3390/s22031264. PMID: 35162009; PMCID: PMC8838436.

Stanchina, M., Abu‐Hijleh, M., Chaudhry, B., Carlisle, C. C., & Millman, R. P. (2005). The influence of white noise on sleep in subjects exposed to ICU noise. Sleep Medicine, 6(5), 423–428. https://doi.org/10.1016/j.sleep.2004.12.004

Sarah C. Hugh, Nikolaus E. Wolter, Evan J. Propst, Karen A. Gordon, Sharon L. Cushing, Blake C. Papsin; Infant Sleep Machines and Hazardous Sound Pressure Levels. Pediatrics April 2014; 133 (4): 677–681. 10.1542/peds.2013-3617

Understand noise exposure | NIOSH | CDC. (n.d.). https://www.cdc.gov/niosh/topics/noise/preventoccunoise/understand.html