First-Night Effect: Why Sleeping in a New Place Feels

What Is the First-Night Effect in Sleep?

Researchers have recognized the first-night effect since early laboratory sleep studies. Compared with later nights, the first night may involve taking longer to fall asleep, spending more time awake, obtaining less total sleep, and experiencing changes in normal sleep architecture. The effect is one reason sleep laboratories have traditionally considered using an adaptation night before collecting measurements intended to represent a person's usual sleep.

The phenomenon does not necessarily indicate insomnia or another sleep disorder. An unfamiliar mattress, different sounds, altered temperature, travel schedules, anticipation, and concern about being monitored can all disturb sleep. For many people, sleep improves as the environment becomes familiar, although the strength and duration of the effect vary.

Why Does the Brain Stay More Alert in a New Place?

A 2016 study in Current Biology found hemispheric differences in slow-wave activity during the first night of laboratory sleep. The researchers also observed greater responsiveness to unusual sounds in one hemisphere, supporting the idea that part of the sleeping brain maintains a form of environmental vigilance.

This response has been compared cautiously with unihemispheric sleep in certain animals, but humans do not normally sleep with one entire hemisphere fully awake. Instead, the evidence points to a subtler imbalance in sleep depth and sensory monitoring. The proposed mechanism is scientifically plausible, but it does not explain every disrupted night away from home.

How Can You Sleep Better in an Unfamiliar Place?

Travelers can support sleep by maintaining a regular bedtime when practical, limiting late caffeine and alcohol, and making the room dark, quiet, and comfortably cool. Familiar items, such as a pillowcase or a consistent background sound, may reduce novelty, although these approaches have not all been tested specifically as treatments for the first-night effect.

A single poor night in a hotel or sleep laboratory is usually not a medical emergency. Persistent difficulty sleeping at home, substantial daytime sleepiness, loud snoring, witnessed breathing pauses, or impaired daily functioning deserves clinical attention. People should avoid starting sleep medicines solely for travel without discussing benefits, risks, and possible interactions with a qualified healthcare professional.