directly, especially when related to seasonal affective disorder. Individuals with breathing difficulties due to asthma or allergies may experience additional barriers to quality sleep that can be addressed by specific variations of sleep hygiene recommendations. Difficulty with breathing can cause disruptions to sleep, reducing the ability to stay asleep and to achieve restful sleep. For individuals with allergies or asthma, additional considerations must be given to potential triggers in the bedroom environment. Medications that might improve ability to breathe while sleeping may also impair sleep in other ways, so there must be careful management of decongestants, asthma controllers, and antihistamines. Implementation Sleep hygiene strategies include advice about timing of sleep and food intake in relationship to exercise and sleeping environment. Recommendations depend on knowledge of the individual situation; counselling is presented as a form of patient education. As attention to the role of sleep hygiene in promoting public health has grown, there has been an increase in the number of resources available in print and on the internet. Organizations running public health initiatives include the National Sleep Foundation and the Division of Sleep Medicine at Harvard Medical School, both of which have created public websites with sleep hygiene resources, such as tips for sleep hygiene, instructional videos, sleep hygiene self-assessments, poll statistics on sleep hygiene, and tools to find sleep professionals. A cooperative agreement between the U.S. Centers for Disease Control and Prevention and the American Academy of Sleep Medicine was established in 2013 to coordinate the National Healthy Sleep Awareness Project, with one of their aims being to promote sleep hygiene awareness. History While the term sleep hygiene was first introduced in 1939 by Nathaniel Kleitman, a book published in 1977 by psychologist Peter Hauri introduced the concept within the context of modern sleep medicine. In this book Hauri outlined a list of behavioral rules intended to promote improved sleep. Similar concepts are credited to Paolo Mantegazza who published a related original book in 1864. The 1990 publication of the International Classification of Sleep Disorders (ICSD) introduced the diagnostic category Inadequate Sleep Hygiene. Inadequate sleep hygiene was a subclassification of Chronic Insomnia Disorder in the ICSD-II published in 2005; it was removed from the 2014 ICSD-III along with two other classifications, because "they were not felt to be reliably reproducible in clinical practice." Specific sleep hygiene recommendations have changed over time. For example, advice to simply avoid sleeping pills