Dutch researchers used high-tech methods to track the nighttime movements of 17 healthy volunteers over five nights. Some of the participants slept with a bedroom door or window open, allowing for better ventilation in the room, while others did not.
The result: The better-ventilated rooms had lower levels of carbon dioxide in the air (humans breathe out CO2 naturally) and that seemed tied to better sleep, according to a team led by environmental researcher Asit Kumar Mishra, of Eindhoven University of Technology.
“Lower carbon dioxide levels [in the bedroom] implied better sleep depth, sleep efficiency, and lesser number of awakenings,” Mishra’s team reported Nov. 22 in the journal Indoor Air.
One U.S. sleep expert said the nighttime environment is important to good slumber.
“This study does remind us that all bedrooms are not equal, and the quality of our sleep is certainly influenced by physical properties of our surroundings at night,” said Dr. Steven Feinsilver. He directs the Center for Sleep Medicine at Lenox Hill Hospital in New York City.
He said while it’s long been known that people sleep better in cooler environments, “the issue of indoor air quality as it might relate to sleep quality is not something that has been given much attention.”
Further and even more meticulous research could offer deeper insights, Feinsilver added.
“The authors were not able to employ the most sensitive measures of sleep, and formal sleep testing including EEG [brain waves] might be more revealing under these conditions,” he said.