Sleepyland is a sound machine in your browser. It generates brown, pink, or white noise and ocean surf on your device as you listen, with no recordings, account, or ads. Tune the color, the warmth, and the time between waves.
Press play: sleepy.land
Ben Guo
The guides below cover sleep, sound, and light. Each one starts with a plain answer and links its sources.
18 articles
Evening screens combine light, arousal, and lost sleep time. Blue-blocking glasses filter very differently, and a meta-analysis of objective sleep outcomes found no significant benefit. A screen-free wind-down is a reasonable low-cost experiment.
Light matters; glasses trials remain small and inconsistent
Offload specific tasks, give each worry a next step, stop checking the clock, and ease the struggle to fall asleep. These steps follow the logic of CBT-I.
Small direct trials plus strong CBT-I principles
Noise, nature sounds, music, earplugs, and silence solve different problems. Start with what keeps you awake. No sound ranks first for everyone.
No universal winner; evidence varies by sound and problem
A pitch, a binaural difference, an EEG rhythm, and a noise spectrum can all be labeled in hertz. They are not interchangeable, and no single audible frequency is proven to cause sleep.
Frequency terms are real; single-Hz sleep claims are unproven
Masking does not erase sound. It changes audibility by adding energy near the frequencies and moments that carry the unwanted signal, while reducing contrast against the room's baseline.
Acoustics established; sleep benefit depends on the disturbance
Adult guidance says at least seven hours on a regular basis. Eight is a planning number with no sharp cutoff, and experiments show why six can feel easier than it performs.
Seven-plus is guidance, not an eight-hour law
Studies of contemporary foragers find shorter, flexible sleep timed by the environment, with no single ancestral pattern to copy.
Field evidence is diverse, ecological, and easy to overread
The first night in a new place is often lighter and more fragmented. Brain-vigilance studies explain part of it, but hotel noise, temperature, travel timing, and expectation still matter.
A real laboratory effect, not a complete hotel diagnosis
Morning outdoor light can strengthen an earlier circadian signal, especially when evenings are dimmer. The effect depends on biological timing, intensity, duration, spectrum, season, and prior light.
Strong clock mechanism; no universal minutes prescription
There is no universal best sound for focus. The useful choice depends on whether you are masking speech, supporting a repetitive task, reading language, or trying to make a session easier to begin.
Effects depend on listener, task, and sound
A short bedtime sound, continuous pink noise, and traffic masking test different uses of sound. Comparing their results means looking at the listeners, the sound, and the outcome each study measured.
Evidence mixed; effects depend on the problem and protocol
There is no evidence-based universal slider percentage, decibel target, or bedside distance. A better setup starts with the noise you are solving, measures where your head rests, and uses the lowest level that changes the interruption.
Practical setup; no universal bedroom level
Masking adds sound, earplugs reduce sound at the ear, and active cancellation creates an opposing signal near the ear. Choosing well starts by naming the operation you need, not by buying three products that solve different problems.
Mechanisms clear; direct sleep comparisons limited
A fan combines several experiences that search results often collapse into “white noise”: broadband airflow, mechanical tones, cooling, moving air, and a learned bedtime cue. The sound may help, but the closest direct home study did not find a significant sleep benefit.
Plausible mechanisms; direct sleep benefit unproven
White, pink, and brown noise differ in how their energy spreads across pitch. That changes what each covers and how loud it feels. No color has been shown to help sleep more than the others.
Physics established; sleep superiority unproven
Ocean sound combines masking, slow energy changes, natural variation, and learned meaning. Those mechanisms are plausible; direct proof of better sleep in healthy adults is still limited.
Relaxation evidence stronger than sleep evidence
The sleepy passenger effect has names: motion-induced drowsiness, vestibular stimulation, whole-body vibration, and, in a stronger form, sopite syndrome. Sound is only one part of it.
Physical-motion mechanism supported
A steady cabin rumble and an aircraft passing over a bedroom are acoustically and psychologically different. One can become a familiar masker; the other is an intermittent sleep disruption.
Plausible masking and cue; no direct proof
Written and edited with AI, with sources linked throughout. Published by Hraness.
The guides are educational and are not medical advice. No clinician has reviewed them.
