8.11 Substances and Sleep

Caffeine

Caffeine is a stimulant found in coffee, tea, soda, and other products and is commonly used to increase alertness. Caffeine is absorbed rapidly by the body into the bloodstream and levels usually peak around two hours after consumption (Mandel, 2002; Nawrot et al., 2003). Caffeine consumption is not inherently dangerous; caffeine increases alertness and reduces drowsiness and fatigue by interacting with neurotransmitters in the brain (Elmenhorst et al., 2012). While lower doses of caffeine—250 mg—are shown to produce more favorable effects related to improved performance and mood, higher doses—500 mg or more—do not lead to enhanced performance and even led to more unfavorable effects like nausea and tension (Kaplan et al., 1997). For reference, a typical eight-ounce cup of coffee contains about 95 mg of caffeine. High doses of caffeine and misuse of caffeinated products—particularly pure or highly concentrated caffeine products—can be toxic or fatal (U.S. Department of Health and Human Services, Food and Drug Administration, Center for Food Safety and Applied Nutrition, 2018). Further, caffeine consumption, particularly as bedtime approaches, can influence circadian rhythm, making it more difficult to get adequate sleep (Burke et al., 2015). If you do consume caffeine, pay attention to how well you sleep after consumption and experiment with various cutoff times to see if this may be impacting sleep. You might also consider gradually cutting down the amount of caffeine to avoid uncomfortable withdrawal symptoms, like headaches.

Nicotine

Nicotine is also a stimulant and can prevent good, deep sleep (Jaehne et al., 2009). The use of products containing nicotine, including cigarettes, smokeless tobacco, e-cigarettes, or vaporizers, might help explain ongoing or occasional sleep disturbances. The addictive quality of nicotine may also lead users to wake up with cravings, leading to poor sleep. Addressing nicotine dependence is a recommended research-based approach to addressing sleep concerns (Dugas et al., 2017). If waking up because of cravings is causing poor sleep, using a nicotine patch at bedtime could help curb these cravings (Aubin et al., 2006).

Alcohol

Contrary to popular belief, having an alcoholic drink before bed—often referred to as a nightcap—won’t help someone sleep better. Although alcohol is a depressant drug and may help someone feel sleepy or fall asleep, sleep disturbances are common in the second half of the sleep session, which is when the majority of REM sleep takes place (Chan et al., 2013). Thus, alcohol actually inhibits the sleep that our bodies need, and it has been shown to negatively impact next-day alertness and performance (Roehrs & Roth, 2001). Regular heavy drinking is associated with overall shorter sleep duration, resulting in sleep deprivation (Singleton & Wolfson, 2009).

Cannabis

Cannabis is a plant with psychoactive properties. Though cannabis withdrawal can cause sleep disturbances (Gates et al., 2016), cannabis has also been shown to reduce dependence on medications for certain conditions, including prescribed sleep medications (Piper et al., 2017). Cannabis does appear to impact sleep architecture (Nicholson et al., 2004) and some research shows that more frequent use is associated with greater sleep disturbances (Maple et al., 2016). Ultimately, the relationship between cannabis use and sleep requires further study. Similar to caffeine, if an individual is experiencing sleep disturbances, use of cannabis should be considered along with other potential influences so appropriate changes can be made to ensure adequate sleep.