Sonic Tonic — SPACE FOR JUSTICE

Millions of people in cities rely on recorded nature sounds to manage sleep and stress, and scientists are slowly understanding why it works.

When Cale Holmes moved from Virginia to New York City for grad school, he started to have trouble sleeping.

All night long the trains thundered past his building, garbage trucks groaned, and police sirens wailed. In the mornings he was awoken by the sounds of construction: hammers banging, machines drilling, men shouting. He began to wear himself out every night before he got home, studying into the wee hours of the morning or hanging in bars drinking beer until he was ready to drop with exhaustion.

But one night, Holmes recalled how calm he used to feel whenever he visited a beach. He went to YouTube and ran a search for ocean sounds. Innumerable recordings of ocean waves popped up, some as long as 12 or 14 hours. He selected a nighttime version and let his room fill with the sound of the crashing of waves. He could also hear the wind howl and the cicadas chirp in the distance.

He lay back on his pillow.

The next thing he knew, warm sunlight was filtering in through the curtains. When he checked his laptop, he saw that the recording had paused at just after four minutes when the laptop had powered off.

Holmes had slipped into sleep effortlessly. “And I felt much better about the day the next morning,” he told me. “I felt my sleep was better. I even felt I had more self-esteem.”

How had the recording helped him so much? Was it that the sound had created a cocoon against the city noises? Or was there more to it? Several teams of researchers around the world have tried to find answers to these very questions.