Making noise to help you sleep sounds counterintuitive. After all, wouldn’t noise keep you awake? But some sleepers find a certain kind of noise helps them sleep better and longer. This is called white noise.

Scientists describe white noise as a sound that continues repetitively at a medium frequency. White noise is always around us, and we frequently hear it in our daily activities without noticing. White noise can be the sound of a ceiling fan, a recording of waves crashing on a beach or the sound of a gentle rain. There are machines designed to provide white noise all night, as well as apps for a tablet or smartphone.

How does white noise help you sleep? There are three ways.

First, your hearing continues to work while you’re asleep, and a sudden loud noise could jolt you awake. White noise creates a masking effect for sudden, unexpected noises.

Second, steady sound can soothe and quiet an active brain. Instead of working through to-do lists, the brain begins to focus on the sound. People often use white noise machines to meditate.

Third, white noise can help you build a bedtime routine. If you turn on the sound as you’re preparing for bed, your body will begin to acknowledge it as a sign that it’s time to power down and sleep.

It’s important to know that not everyone sleeps better with white noise. In fact, some people develop a greater sensitivity to underlying sounds and frequently wake during the night. If you think your sleep troubles may need professional help, contact your doctor.

For the rest of you seeking some much-needed rest, switch on some white noise, enjoy the waves on the beach, and catch some much-needed sleep.