A 2017 study from the Netherlands has presented an intriguing answer to the question many people ask: "Should I sleep with window open?" It suggests that keeping your bedroom door or window open may be the key to better sleep quality. Admittedly, for those of us living in tropical climates like Singapore, the thought of sleeping with windows open, without the air-con on, conjures images of everything in the house, including your adorable kitten, melting from the heat. However, it's not about temperature control in this context. We're talking about ventilation. While you'll have to figure out how to deal with the heat (a fan could help?), it turns out that opening a window or a door can significantly reduce carbon dioxide levels and improve the ventilation in the room, leading to better sleep quality. The Impact of Sleeping with Window Open on Sleep Quality As the study's author, Dr Asit Mishra, pointed out, "We spend nearly a third of our lives in the bedroom environment, but the air quality in our sleeping environment is often overlooked.” To test the benefits of sleeping with window open, 17 volunteers were involved in an experiment where various aspects of their sleep environment and physical responses were monitored. The volunteers were each given an armband that measured their skin temperature, heat flux, bed temperature, and moisture levels. They also had a sensor to track their movements at night, indicating how restless they were. The Benefits of Open Windows at Night When the study concluded, it was clear that sleep quality improved as carbon dioxide levels decreased. Dr Mishra further commented, "Opening an internal door can be a reasonably good alternative if you don’t want to open windows, either for noise concerns or security concerns.” “Sleep quality is affected by many factors, such as health and emotional states, bedding conditions and different environmental conditions, including noise levels and temperature,” added Dr Nuno Canha of the University of Lisbon in Portugal. In a separate study led by Dr Canha, it was discovered that sleeping with windows closed led to higher levels of carbon monoxide, carbon dioxide, and substances such as formaldehyde. The Consequences of Sleeping with Windows Closed Formaldehyde? That's something you don't want in your bedroom. If the research is anything to go by, you might want to consider opening your windows and doors tonight (mosquito army notwithstanding). You may wonder, would an air conditioner achieve the same result? Unfortunately, this remains uncertain as the studies were conducted in regions where household pets wouldn't succumb to the heat. However, the key takeaway is clear: the reduction of carbon dioxide in your sleeping environment is essential. Dr Canha advises, "The exposure we are under while asleep is continuous... and we should play it safe in order to breathe better air during sleep.” So, the next time you're pondering the question, "Should I sleep with window open?", consider the potential benefits for your sleep quality.