Sleep problems are often attributed to stress, screen use, or irregular bedtimes.
However, research suggests that the bedroom environment itself can play a significant role in sleep quality, with temperature being one of the most underestimated factors.
According to a review by Real Simple, small changes in bedroom conditions can have a noticeable effect on how well people sleep.
Temperature becomes particularly important during periods of large fluctuations in weather conditions and energy use.
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At the same time, researchers stress that the evidence is not unequivocal. The conclusions are based on a combination of laboratory studies and observations from everyday life.
The temperature
A research review published in Energy and Buildings shows that warm rooms can interfere with the deepest stages of sleep.
This effect is especially pronounced in environments with high humidity, which makes it more difficult for the body to dissipate heat.
Other studies, including research discussed in Neurological Research, indicate that the body naturally lowers its core temperature in the evening.
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This cooling process is linked to the production of the sleep hormone melatonin.
A cooler bedroom can support this process, although the impact varies from person to person.
When comfort affects sleep quality
According to Nature and Science of Sleep (1), frequent awakenings during the night can lead to reduced concentration and increased fatigue during the day.
Rooms that are too warm raise the risk of restlessness, while overly cold environments can cause discomfort, even if the structure of sleep itself is not significantly altered.
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As a result, both physiological processes and perceived comfort influence overall sleep quality.
The recommended temperature range
Many experts point to a bedroom temperature of approximately 18 to 22 degrees Celsius, with around 18 degrees often cited as a practical starting point.
Bedding choices can also play an important role in regulating body temperature during the night.
A study published in Nature and Science of Sleep (2) shows that materials such as wool, cotton blends, and bamboo, as well as cooling duvets, blankets, and pillows, can help draw heat and moisture away from the body and contribute to more comfortable sleep.
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The key, therefore, is not a single ideal number, but making small adjustments that can meaningfully improve sleep quality.
Sources: Real Simple, Energy and Buildings, Neurological Research, Nature and Science of Sleep (1), and Nature and Science of Sleep (2).
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