Sleep hygiene is the controlling of "all behavioural and environmental factors that precede sleep and may interfere with sleep."
It is the practice of following guidelines in an attempt to ensure more restful, effective sleep which can promote daytime alertness and help treat or avoid certain kinds of sleep disorders. Trouble sleeping and daytime sleepiness can be indications of poor sleep hygiene or sleep habits. The International Classification of Sleep Disorders-Revised
(ICSD-R) states on page 74: "The importance of assessing the
contribution of inadequate sleep hygiene in maintaining a preexisting
sleep disturbance cannot be overemphasized." In the ICSD-R, the diagnosis inadequate sleep hygiene is classified as an extrinsic sleep disorder, code 307.41-1.