A new literature review examines how noise machines impact sleep.

For the new study, researchers scoured the medical literature for studies that examined the impact of white noise on sleep. In the end, they turned up 38 studies, most quite small, that attempted to address the issue. The studies were all over the map in terms of methodology, too. Some used sleep labs to measure the impact of white noise, while others depended simply on participants’ self-reports on sleep quality.

The dearth of good evidence came as a surprise to study co-author, Dr. Mathias Basner, a professor in the department of psychiatry at the University of Pennsylvania Perelman School of Medicine in Philadelphia.

There was a suggestion in some of the studies that white noise might help a person doze off quicker, but there were also hints that white noise played throughout the night might result in fragmented sleep, Basner said.

Get the full story at today.com.