Many people believe that sleeping with the window slightly open “promotes better sleep” and gives a sense of freshness. However, experts warn that this habit “can present risks that are often underestimated.”

Sleeping with the window open exposes you to sudden temperature changes, which “disrupt your sleep cycle” and make rest less restorative. Outdoor air also brings allergens like pollen and dust that “cause sneezing, irritation, and respiratory discomfort,” especially for sensitive people. Noise from traffic or voices can easily wake you, and even brief awakenings “increase fatigue upon waking.”

An open window can also cause a feeling of insecurity that “affects relaxation and delays falling asleep.”

Fortunately, keeping windows closed doesn’t mean breathing stale air. Opening them during the day renews the air, while a quiet fan or purifier “filters out harmful particles” and maintains a pleasant temperature. Morning ventilation helps remove moisture and pollutants, promoting “better breathing during sleep.”

Experts conclude that while sleeping with the window open seems natural, “the risks are real.” Stable temperatures, reduced noise, and a sense of safety make closing the window at night a simple yet effective way to improve sleep quality.