July 24, 2026, 11:19 am | Read time: 4 minutes
The first night on vacation in a hotel, in a new apartment, or staying over at friends’—you can’t sleep well, toss and turn, and wake up frequently. Sleep research has proven that this phenomenon is not just a subjective perception but a real occurrence. The so-called “First Night Effect” even leads to sleep data from the first night in a sleep lab being disregarded. FITBOOK explains what’s behind it.
The “First Night Effect” (FNE) describes the situation where we initially sleep worse in a new environment than at home. Sleep disturbances typical of the first night have been made visible through data collected in sleep labs. The sleep data revealed what many surely know from personal experience on vacation or after moving: It takes longer to fall asleep, you sleep shorter overall, less well, and wake up more often.
Research on the “First Night Effect”
The “first night” effect was first described in 1966.1 In 2022, a meta-analysis of 53 studies on the FNE confirmed that the first night in a new environment is particularly affected, while it significantly decreases by the second night. However, some people experience sleep disruptions for up to four nights.2,3 Apparently, the effect does not affect everyone equally. Research has found that people who generally have lighter sleep or are more anxious are more likely to experience the “First Night Effect.”
Why Does a New Environment Disrupt Sleep?
In 2016, researchers discovered that the brain does not fully “shut down” during the first night in a new place. One hemisphere remains in a lighter sleep phase and acts almost like a sentinel, while the other enters a deeper sleep.4 The assumption is that this asymmetry is an evolutionary adaptation, as new, unfamiliar places historically posed potential dangers that were not immediately assessable. Similar behavior is observed in some bird species and marine mammals, which sleep with one eye open for safety reasons.
Further insights into what causes the “First Night Effect” and what happens in the body were provided by a 2024 study. It showed that new sounds, smells, lighting conditions, or even the bedding trigger increased activity in the limbic system, particularly in the amygdala (a region in the brain specialized in detecting potential threats). This leads to fragmented sleep, more frequent micro-awakenings, and a reduced amount of restorative deep sleep.5
The internal clock also plays a role in sleep disturbances in a new environment.6 It can become disrupted due to unfamiliar light and noise influences, as well as changes in evening routines and shifts in meal times and daily activities. This further complicates falling and staying asleep.
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Significance of the “First Night Effect”
For many people, the phenomenon mainly provides an explanation for why they sleep poorly at the start of their vacation or after a move. And they now know that the effect quickly dissipates.
Sleep researchers and physicians take the “First Night Effect” into account in studies and examinations. They know that the data from the first night often does not reliably reflect normal sleep behavior—neither for study participants nor for people visiting a sleep lab due to suspected sleep disorders.
What Helps Reduce the Effect?
Research has shown that a few tricks can promote sleep in a new environment. Bringing familiar items, such as your usual pillow from home or a beloved blanket, can be helpful. Familiar scents also enhance well-being in a new place. Measures that generally support healthy sleep can also help in these situations. Try to avoid exposure to blue light as much as possible in the second half of the day, and maintain usual meal times and evening rituals. If you need to perform well the next day, such as on a business trip, consider arriving a night earlier to shift the impact of the “First Night Effect” to the day before the important event.