When people spend a night in an unfamiliar environment, they often experience disrupted sleep known as the first-night effect, according to sleep researchers. This phenomenon causes individuals to fall asleep later, wake more frequently, and get less overall rest compared to nights spent in their own homes.
Robinson Leoni, a sales director who travels regularly for work, described his own experience. While he typically averages seven hours of sleep at home, his smartwatch tracks only about five hours on the first night of travel, regardless of sleeping conditions or use of earplugs. “I feel normal, no stress, but I notice I wake up continuously,” Leoni said.
Experts view the first-night effect as an evolutionary adaptation intended to keep the brain alert in unfamiliar surroundings. Anna Wick, a senior sleep researcher at the University of Freiburg in Switzerland, explained that this increased vigilance is believed to have helped ancestors stay aware of potential threats in new places. “It’s assumed to be an adaptation response that the sleeping brain remains vigilant in this unfamiliar environment,” she said.
Ahmad Mayeli, a psychiatry professor and sleep researcher at the University of Pittsburgh, noted that most people experience some degree of this effect, even if they are unaware of it. His research points to increased activity in the frontal lobe during the deepest sleep stages, suggesting that while parts of the brain are deeply asleep, others remain more alert. “Like in dolphins, part of the brain is awake when you are sleeping,” Mayeli said, though he clarified it is not as pronounced as in marine mammals.
Age also influences the severity of the effect, Mayeli added. Children, adolescents, and older adults tend to experience more pronounced disruptions, while individuals in their 20s are generally less affected. He speculated that the brain remains cautious in unfamiliar environments due to historical risks associated with new places. “It doesn’t matter if it’s a Marriott hotel or it’s the savannah. Your brain hasn’t gotten the memo that this place is completely safe,” Mayeli said.
Wick suggested the disruption typically fades after the first night. However, Lisa Strauss, a psychologist specializing in cognitive behavioral therapy for sleep disorders, emphasized that factors beyond evolutionary vigilance can affect sleep quality in new environments. Travel fatigue, even within the same time zone, environmental irritants such as flashing lights from smoke alarms, and interpersonal stress from strained family visits can all contribute to disturbed sleep.
Strauss noted some individuals might actually sleep better in a new location if they arrive exhausted or find the setting removes everyday stressors. She also mentioned those with existing insomnia may benefit from a change of scenery if the new setting lacks associations with prior sleep difficulties. People with higher baseline anxiety, however, are especially susceptible to the first-night effect and may struggle more to relax in unfamiliar places.
Overall, while sleep disturbance in new environments is common and often temporary, it reflects the complex interplay of biological, psychological, and situational factors governing rest.