Ancient Brain 'Night Watch' Linked to Poor First-Night Sleep on Trips

Travelers often experience difficulty sleeping in new locations due to a phenomenon called the first-night effect. Science suggests that during the initial night in an unfamiliar place, part of the brain remains unusually vigilant, acting as a "night watch" to monitor the surroundings while the rest of the body attempts to rest.

What Happened

This increased alertness in a new environment can result in longer times to fall asleep, more frequent awakenings, reduced total sleep duration, and diminished sleep efficiency, including less REM sleep. Research indicates that the first-night effect might not be solely due to unfamiliar settings but can also be influenced by changes in routines or the experience of being monitored. A study published in Current Biology proposes that one hemisphere of the brain may stay more vigilant during deep sleep in a new place, an adaptation possibly rooted in ancient survival instincts that aided ancestors in unfamiliar territories.

Why It Matters

The consequences of the first-night effect extend beyond mere tiredness. Studies have shown that this sleep disruption can impair the brain's overnight processing, reducing the benefits for visual learning and altering neurochemical processes linked to brain plasticity. This suggests that even short periods of disturbed sleep can interfere with essential cognitive functions.

Background

Up to 80 percent of travelers report experiencing poorer sleep away from home, according to the Clayton Sleep Institute. While unfamiliar mattresses can contribute, sleep quality is affected by a complex interplay of cues including light, routines, surroundings, and perceived safety, all of which can be disrupted by travel. Other factors contributing to travel insomnia include the misalignment of the body's internal clock with local time zones, disruptive travel experiences like airport crowds and tight connections, and lifestyle adjustments such as caffeine intake, alcohol consumption, and late meals.

Key Facts

• Up to 80 percent of travelers report poorer sleep away from home.
• The first-night effect leads to longer sleep onset, more frequent awakenings, and reduced sleep efficiency and REM sleep.
• Research suggests one brain hemisphere may remain more vigilant during deep sleep in a new environment.
• The first-night effect can reduce benefits for visual learning and alter neurochemical processes associated with brain plasticity.
• Time zone changes, travel-related stress, and changes in diet and routine also contribute to travel insomnia.