Sleep hygiene: A series of practices and non-medical treatments for insomnia. Sleep hygiene includes simple steps that may improve initiation and maintenance of sleep, such as maintaining a regular sleep schedule, making the bedroom an inviting place to sleep, avoiding alcohol, large meals, or smoking prior to going to bed, and exercising regularly (but not in the 4-5 hours prior to bedtime).
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.