The 'first-night effect': Why it's hard to sleep when you're somewhere new
Medical Xpress
February 23, 2026
AI-Generated Deep Dive Summary
Sleeping in a new environment can be challenging due to what’s known as the "first-night effect." This phenomenon occurs when your brain struggles to fully relax in unfamiliar surroundings, making it harder to fall asleep or stay asleep. Factors like strange noises, unusual lighting, and even subtle changes in temperature can disrupt your usual sleep patterns. While this experience is common, understanding its causes and how to mitigate them can help travelers and anyone spending time away from home get the rest they need.
The first-night effect is rooted in our evolutionary history. Early humans likely needed to stay alert in new environments to detect potential dangers, which means one side of the brain remains more awake while the other tries to rest—a phenomenon known as "unilateral sleep." This survival mechanism can still kick in today, leading to lighter sleep stages and increased responsiveness to external stimuli like car horns or unfamiliar sounds. For travelers, this can result in feeling groggy or less productive the next day due to poor-quality sleep.
Fortunately, there are strategies to combat the first-night effect. Creating a calming environment is key. Using white noise machines or apps can mask unsettling background noises, while wearing an eye mask or using blackout curtains can help block out unfamiliar lighting patterns. Adjusting the room temperature to your usual comfort zone and avoiding electronic devices before bed can also improve sleep quality in new settings. Additionally, gradually exposing yourself to novel environments through shorter
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Originally published on Medical Xpress on 2/23/2026