When white noise is too noisy: Don’t crank that machine to eleven

The Pediatric Insider

© 2014 Roy Benaroch, MD

I like white noise to help babies sleep. It seems to mask other sounds, and when used routinely becomes a nice sleep-cue for newborns, infants, and older kids. White noise machines, or “generators”, are routinely sold at baby stores, and there’s (of course) even an app that will make your phone create that static-like, whooshing or raining noise.

Yup. An app. That makes your phone sound like a 1970’s clock radio tuned between stations. I knew I shouldn’t have let my mom throw that away.

Anyway: as with all things in life (except coffee), there can be too much of a good thing. So says a new study from Pediatrics, “Infant Sleep Machines and Hazardous Sound Pressure Levels”. Researchers from Canada tested 14 ordinary white noise generators that are marketed to parents as sleep helpers to see how loud they could be when cranked up to maximum volume. They re-created a crib sleeping environment, and tested sound levels with the devices right at the crib rail, or on a table next to the crib, or across the room.

Now, there really isn’t a single standard for white noise, but for hospital nursery equipment an accepted noise threshold is to keep volume under 50 dB (decibels) for one hour’s exposure. In real life, potential damage to hearing depends both on the intensity (volume) of the sound, its frequency, and its duration; other factors like ear shape and the overall health of the baby are probably important, too. But the 50 dB threshold is probably a fair approximation of a volume that shouldn’t be exceeded, at least not for more than an hour or so. 50 dB is about what the volume of a shower sound like when you’re standing in the bathroom—a little louder than ordinary speech, but you could talk over it by speaking up a bit.

What the researchers found was that all of the devices exceeded 50 dB when turned up to maximum, as measured right nearby (as if the device was in or right near the crib.) Most of them exceeded 50 dB even when placed six feet away. Again, though, these were all tested at maximum output, with the dial turned up to 10 (or, perhaps, 11). The loudest of the devices came in at 93 dB, about as loud as a hand drill. For comparison, a rock concert is about 115 dB.

This study didn’t measure the effects of this level of noise on actual babies, and in fact there really isn’t any good data about just how loud/how long white noise needs to be to affect hearing development. Still, the study shows that these things can get pretty loud, and that may not be a good thing.

However, neither is a screaming, restless baby. Those get pretty loud, too—much louder than 50 dB. Mom and dad’s hearing (and sanity) are important, too.

The authors of the paper call on manufacturers to label their products informing parents of the danger of loud noise, and of limiting the devices’ sound output.

Let me also recommend some common sense: when you use these things, don’t turn them up to maximum and let them run all night. You can safely use a white noise machine reasonably, turned up half-way, or something like that. If it is hard to speak over the noise it’s making, it’s probably too loud. Junior might sleep better with some white noise, but I don’t think he’s quite ready for Crazy Train.

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One Comment on “When white noise is too noisy: Don’t crank that machine to eleven”

  1. William JTucker Says:

    I use white noise for myself. I have to have a fan or something running at all time or I get very nervous. (Yeah, I guess I am just weird). I have a very hard time sleeping without some form of background noise. I use a fan in my kids’ room mostly because they go to bed before my husband and I do so it masks the sound of us talking or the TV or whatever. As long as you are not using it at a stupidly loud volume, I don’t see how a white noise machine will damage your baby’s hearing.


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