Y: Today, white noise machines and sound apps abound for those in search of a better night’s sleep. Background white noise can help some peoples’ sleep quality by minimizing the length of time it takes them to get to sleep. So, what exactly is white noise, Don?

D: It’s a consistent signal that’s produced at equal intensities across all frequencies, Yaël— at least across those that we can hear. When we’re trying to fall asleep, white noise can create a masking effect that blocks sudden changes in sound.

Y: That’s interesting because, usually, our brains only arouse us from sleep when a sudden rupture of sound creates an inconsistency in the room or somewhere nearby. So, white noise helps to cancel out those bursts of noise.

D: That effect benefits people most when they’re settling down to sleep. In a 2017 study, researchers at Harvard found that subjects who listened to white noise while falling asleep actually fell asleep in around sixteen to twenty minutes. This sleep onset period was about 40% shorter than for those who didn’t listen to white noise while they dozed off.

Y: The total amount of time that these people slept didn’t change based on whether they listened to white noise. A fan or a rain shower sound loop might help some people get to sleep, but it won’t help them sleep longer.

D: The real benefit of using white noise to improve your sleep is that it reduces the amount of time it takes to doze off if you have trouble falling asleep. White noise can also promote deeper and less fragmented sleep because it insulates against noise outside so that you get better quality rest.