How White Noise Helps Us Sleep

White noise may be the key to getting a full night's rest, and a fan could do the trick on the cheap.


Electric fan photo via Shutterstock

Global spending on sleep products is expected to reach $33.2 billion this year, and it’s easy to see why — from herbal treatments to prescription sleeping pills, the market is flooded with things alleging to bring the perfect night’s rest. But according to Dr. Josna Adusumilli, a neurologist in the Massachusetts General Hospital Sleep Center, the solution may already be in your house: a fan.

Fans are so effective, Adusumilli says, due to white noise. Though consumers can buy pricey specialized white noise machines, Adusumilli says the gentle whir of the fan, combined with its ability to bring down room temperature, may be the perfect fix for insomniacs.

But why is white noise, which Adusumilli defines as “random noise that’s generated with contribution from all frequencies,” such an integral part of sleep? It’s less about the noise itself, she says, and more about how it tempers other sounds going on around you. “White noise masks other noises in the environment that may disrupt sleep,” Adusumilli says. “In general it’s the change in sound, rather than the actual sound itself, that causes you to wake up. If there’s also some white noise in the background, there’s less of a change in the sound levels if a new sound pops up.”

Adusumilli says expectation also plays into white noise’s effectiveness. “If you’re in a coffee shop, you hear the sounds of people talking, coffee grinding, and cups clinking,” she says, “but you probably won’t be disturbed by these individual noises because they all blend together as part of the background noise.” Using white noise as a sleep aid works in much the same way — having a constant, expected source of noise can make unexpected noises, like a cup clinking in your kitchen, blend right in instead of becoming a disruption.

That said, Adusumilli says that white noise won’t work for everyone. “Everybody is different,” she says. “Some people who are sensitive to sounds may find that the sound of white noise itself is disruptive.” Still, she recommends giving it a try if you’ve had trouble sleeping in the past, adding that listening to audiobooks can be a relaxing way to ease into sleep as well.

And though there’s no harm in using white noise to fall asleep, Adusumilli says people who do not wish to rely on it to fall asleep can gradually swap other tactics into their nightly routines instead. “Theoretically you can wean yourself off of it by perhaps changing other factors that make it easier for you to fall asleep, such as adjusting the room temperature,” she suggests. “But on the other hand, if you do find that white noise helps you sleep you may wish to use it long term, and I definitely wouldn’t object to that if it helps you fall asleep.”

You may not need a machine that plays the sound of a babbling brook, but next time getting your full eight hours is proving evasive, it can’t hurt to pull out your old fan.