Sleep hygiene studies use different sets of sleep hygiene recommendations,
[12] and the evidence that improving sleep hygiene improves sleep quality is weak and inconclusive as of 2014.
[1] Most research on sleep hygiene principles has been conducted in clinical settings, and there is a need for more research on non-clinical populations.
[1]
The strength of research support for each recommendation varies; some of the more robustly researched and supported recommendations include the negative effects of noisy sleep environments, alcohol consumption in the hours before sleep, engaging in mentally difficult tasks before sleep, and trying too hard to fall asleep.
[8] There is a lack of evidence for the effects of certain sleep hygiene recommendations, including getting a more comfortable mattress, removing bedroom clocks, not worrying, and limiting liquids.
[8] Other recommendations, such as the effects of napping or exercise, have a more complicated evidence base. The effects of napping, for example, seem to depend on the length and timing of napping, in conjunction with how much cumulative sleep an individual has had in recent nights.
[1]
There is support showing positive sleep outcomes for people who follow more than one sleep hygiene recommendation.
[8]
While there is inconclusive evidence that sleep hygiene alone is effective as a treatment for insomnia, some research studies have shown improvement in insomnia for patients who receive sleep hygiene education in combination with
cognitive behavioral therapy practices.
[21]