Table 1.

Summary of key findings and future directions for the application of sleep hygiene to the general population

Sleep hygiene recommendation	Summary of Findings	Directions for future research
Avoid caffeine	• Caffeine administration close to bedtime disrupts sleep • Effects of caffeine on sleep show a dose-response relationship • The impact of morning and afternoon caffeine use is less clear • Harmful effects of caffeine on sleep may be limited to caffeine-sensitive individuals • Tolerance to caffeine's effects on sleep develops within days	• Morning and afternoon caffeine use • Intermittent caffeine use and the importance of day-to-day variation • Tolerance and habituation • Identification and targeting of caffeine-sensitive individuals
Avoid nicotine	• Acute and chronic nicotine administration/smoking disrupts sleep • Arousals increase temporarily during acute nicotine withdrawal • Few/limited studies suggest sleep problems associated with smoking can be resolved after cessation and withdrawal	• Longitidunal assessments of change in sleep from pre- to post-cessation • Threshold for occasional and/or light use to impact sleep • Extent to which passive smoking disrupts sleep
Avoid alcohol	• Acute alcohol administration before bed decreases SOL but increases arousal during second half of night • The effects of alcohol on sleep are dose-dependent • Tolerance to alcohol's effects on sleep occurs within days • Sleep problems increase during acute withdrawal of dependent users • Despite modest improvement, long-term sleep problems persist in abstinent former users	• Longitudinal assessments of change in sleep during use and abstinence for dependent users • Direct tests of alcohol avoidance effects on sleep in nondependent useres • The impact of afternoon and evening use on sleep • The effect of non-dependent use patterns (e.g., light/occasional, habitual weekend use) • Combined effects of alcohol with nicotine and caffeine on sleep
Exercise regularly	• Regular and/or acute bouts of exercise produce modest improvements in sleep for individuals with and without sleep complaints (though impact of exercise training on PSG-assessed sleep is less consistent) • Current evidence does not support the claim that late-night exercise disrupts sleep	• Extent to which different types, duration, and intensity level of exercise can be specified for optimal sleep improvement • Moderating effects of age, gender, and fitness level on the impact of exercise on sleep
Manage stress	• Psychosocial stress is associated with increased pre-sleep arousal and impaired sleep • Various stress management strategies have been shown to reduce pre-sleep arousal and improve sleep (most often self-reported sleep) • Individual differences influence perception of stress and coping style	• Identify patterns in individual differences to predict those whose sleep is most affected by stress • Examine the isolated benefit of stress management beyond reduction in physiological arousal • Develop process by which individuals can evaluate their own stressors and identify the most appropriate stress management technique for their needs
Reduce bedroom noise	• Nighttime noise increases arousals • Habituation to noises occurs, but EEG arousals persist • Specific noise reduction strategies have been shown to improve sleep in some environments (most often in ICU patients)	• Further test noise-attenuating strategies in home environments using objective sleep assessments • Identify individual-level factors (e.g., age) that influence preference and efficacy of specific strategies
Sleep timing regularity	• Clinical sleep treatments encourage regularity only in wake time, which is counter to some sleep hygiene recommendations to adopt regular bed- and wake-times • Irregular sleep schedules have been associated with poor sleep, but assigning regular sleep schedules to nonclinical adults has shown limited effects on sleep improvement	• Relative importance of bed- vs. wake-time regularity in nonclinical samples • Influence of moderating factors (e.g., chronotype, age) • Threshold for schedule regularity required to promote good sleep
Avoid daytime naps	• Most research suggests that daytime naps do not have a substantial impact on subjective or objective nocturnal sleep, despite sleep hygiene recommendations to avoid naps • Nap duration and timing seem to have limited effects on the relationship between napping and nocturnal sleep	• Impact of nap elimination on nocturnal sleep in habitual nappers with poor sleep • Examination of naps in the home environment rather than laboratory • Moderating effect of age

Note. EEG=electroencephalography; ICU=Intensive Care Unit; PSG=polysomnography; SOL=sleep onset latency.