Understanding the Effects of Caffeine, Nicotine, Alcohol and Cannabis on Sleep

As a sleep medicine physician I am often asked about the effects of commonly ingested substances on sleep. Here is a summary of some of the research regarding the effects of caffeine, nicotine, alcohol and cannabis on sleep.

Caffeine:

Caffeine is a stimulant that helps to improve alertness by counteracting a sleepiness molecule called adenosine which is produced by the brain as it uses energy. Adenosine is supposed to tell the brain that it needs to sleep in order to replenish its energy stores and caffeine blocks the signal from being heard, tricking the brain into thinking that it no longer needs to sleep. Caffeine also gives a wake up signal to our internal clock by suppressing melatonin (our body’s natural darkness hormone). Caffeine from a natural source such as coffee or tea may potentially be beneficial for health in moderation, as numerous studies looking at coffee and tea consumption and mortality have shown a reduction in overall mortality in moderate coffee/tea drinkers when compared to non-drinkers. This research is somewhat limited, however, because around 90% of adults in America consume caffeine daily and many of the people who do not consume caffeine have health problems to start with which prevent them from consuming it. It is not clear that drinking pure caffeine such as in a caffeine pill, caffeinated soda drink or energy drink confers these same benefits and artificially sweetened beverages (including with sugar substitutes such as those in “diet” soda) overall seem to be associated with higher mortality and worsened health.

Unfortunately, our brains become “tolerant” to caffeine after just a few days of use, meaning that we will no longer feel an increase in alertness after around 3–4 days of caffeine ingestion. Once we have been drinking caffeine on a regular basis, our brain begins to expect that it will get caffeine and we will feel sluggish if we do not receive the expected dose at the expected time. When our brain finally does get the expected dose of caffeine, it will basically return to its baseline level of alertness, the same level it functioned at before we ever ingested any caffeine. In order to produce another boost in alertness we will need to increase the amount of caffeine ingested (for instance going from 1 to 2 cups of coffee).

If a person habitually consumes a certain amount of caffeine, reducing the amount of caffeine consumption on a given day or abstaining from caffeine entirely is likely to result in withdrawal symptoms including headache, fatigue, depression, lack of motivation, sleepiness. Caffeine withdrawal can last for a prolonged period of time in some individuals after complete cessation, particularly if they were consuming high levels of caffeine prior to stopping. If a person is interested in stopping caffeine consumption entirely, they should consider slowly reducing the amount of caffeine they consume over time, rather than just stopping abruptly.

In a person who does not habitually consume caffeine, caffeine consumption even in the morning may delay sleep onset at night and reduce sleep quality. Once the brain becomes used to having daily caffeine, however, the effects on nighttime sleep are lessened. In particular, if a person is consuming very large amounts of caffeine (>3–4 cups of coffee per day), ingestion of a small amount of additional caffeine will have very little effect. Such people often assert “caffeine does not affect me, I can drink a cup of coffee and go straight to sleep”. In reality, if that person reduced their caffeine intake or stopped having caffeine entirely they would again be able to notice the effects of evening caffeine. The closer to bedtime that one consumes caffeine, the more likely the caffeine is to impair the quality of nighttime sleep. Even if a person is not aware of a reduction in sleep quality with caffeine we can still usually see one in a sleep laboratory setting. There is also significant variation in the population regarding sensitivity to the effects of caffeine and the duration of time which caffeine remains in the body after ingestion.

Recommendations:

• Be consistent with the timing and amount of caffeine you drink each day.
• If you plan to habitually consume caffeine, obtain it from a natural source such as coffee or tea, NOT from sodas or energy drinks.
• You can strategically supplement an extra “dose” of caffeine if needed for a boost of alertness or a change in sleep schedule, but if you supplement for more than 2 days in a row you may experience withdrawal symptoms (headache, fatigue, depression, lack of motivation, sleepiness) after again reducing to your typical amount. When you do supplement with an extra dose of caffeine, you may also experience worsened sleep quality or difficulty falling asleep that evening (particularly the closer that dose is to your bedtime). You may not be aware of this reduction in sleep quality.
• If you habitually feel that your sleep quality is poor or experience difficulty falling asleep, consider eliminating all caffeine after 12PM (the exact time you need to stop consumption varies between individuals).
• If you are interested in stopping caffeine, consider slowly tapering off, rather than stopping. For coffee drinkers, mix decaffeinated and caffeinated coffee, reducing the percentage of caffeine by 10% each week until you are off. For tea drinkers, slowly transition from tea with a higher caffeine content to tea with a lower caffeine content (see https://the.republicoftea.com/tea-library/caffeine-in-tea/tea-and-caffeine/).
• If you experience frequent urination during the day or night, consider reducing your caffeine intake or stopping entirely. (Caffeine is a bladder irritant and also has diuretic effects which can lead to increased urination).
• If you regularly experience a severe afternoon “dip” in performance which you counteract with caffeine, try stopping afternoon caffeine entirely. Sometimes part of that “dip” is actually caffeine withdrawal and the dip may be less once you have entirely stopped your afternoon caffeine for 1–2 weeks.

Nicotine:

Nicotine is a central nervous system stimulant found in natural sources of tobacco such as cigarettes, cigars and chewing tobacco as well as tobacco replacement products such as vaping fluid and nicotine gum/lozenges/patches. Because nicotine increases alertness, using nicotine-containing substances before or during the night will reduce sleep quality. Nicotine also has a short duration of action of several hours and nicotine withdrawal occurs in chronic users after this period of time which can further disrupt sleep quality. (Most chronic nicotine users report that they actually feel calmer and more relaxed after a dose of nicotine. This calming effect, however, is mostly due to the dose of nicotine counteracting the withdrawal symptoms associated with lack of nicotine for several hours). Smoking, vaping and chewing tobacco products have been linked to a large number of adverse health consequences and cessation is recommended. The long-term consequences of using nicotine replacement products (other than vaping) is unknown at this time.

Recommendations:

• If you currently smoke, vape or chew tobacco, consider quitting for the overall health benefits and sleep benefits.
• If you use nicotine in other forms such as nicotine replacement products, be aware that use of these products within several hours of bedtime or during the night will likely reduce your sleep quality.

(See https://www.huffingtonpost.com/2015/03/05/how-smoking-affects-sleep_n_6792954.html for more information on how smoking affects sleep.)

Alcohol:

The ethanol found in alcoholic beverages is sedating to the central nervous system and is commonly used by the general population to help induce sleep. It turns out, however that although the initial effect of alcohol is sedation, as it is metabolized by the liver, additional substances are produced which actually worsen sleep quality in the second half of the night, leading to an increased number of arousals from sleep. Ethanol seems to actually disrupt the function of the body’s internal clock, reducing sleep drive in the second half of the night and potentially reducing daytime alertness the following day. Ethanol also reduces one of the stages of sleep called Rapid Eye Movement sleep (REM sleep). REM sleep is essential to proper processing of information we learned during the day, emotional regulation, immune system and cardiovascular function and chronic suppression of REM (which can occur with chronic, heavy alcohol use) can lead to impairment of these and other biologic functions. Ethanol causes increased urination at night. Additionally ethanol and other chemicals found in alcoholic beverages can worsen sleep disorders such as obstructive sleep apnea and restless leg syndrome. Even when ingested 4–5 hours before bed, several studies have still shown detectable effects on nighttime sleep quality. Chronic alcohol users who stop using alcohol typically experience severe sleep disruption initially which is often followed by chronic complaints of insomnia.

Recommendations:

• If you regularly ingest alcohol and are experiencing sleep fragmentation or poor sleep quality, consider stopping alcohol use for at least 1 month to see if your sleep quality improves. (If you were ingesting fairly large amounts of alcohol prior to stopping, your sleep may severely worsen before improving and you should speak with a medical provider before making a decision to stop drinking entirely.)
• Try to consume any evening alcohol at least 4 hours before bedtime to reduce the effects on sleep.
• Reducing your alcohol intake and moving it to slightly earlier in the evening without entirely stopping consumption may still result in some benefit to nocturnal sleep.

Cannabis:

Due to the previously illegal nature of cannabis, high quality data on the effects of cannabis on sleep are lacking. Fortunately, interest in studying cannabis is increasing and better quality research studies are actively being conducted. Preliminary data suggests that there may be small reductions in times to sleep onset and nocturnal awakenings initially after cannabis use, but these effects go away over time and ultimately the sleep quality of chronic cannabis users is worse than that of non-users. Multiple observational studies have found that chronic cannabis users report increased sleep disturbances compared to non-users or occasional users. Similarly, while cannabis initially makes people feel less anxious, chronic cannabis use worsens anxiety disorders and can even cause psychosis (visual and auditory hallucinations or chronic paranoia). Additionally, cannabis has a very long elimination half-life (25–36 hours), which makes it ill-suited to use as a sleeping medication since residual effects will be present the following day during wakefulness. After a few days of using cannabis, even if that use only occurs prior to bedtime, cannabis will reach a steady-state equilibrium in the body and be present in significant levels throughout both the day and night. In daily recreational users, THC can be detected for 1 month or more after cessation of use and cognitive function may be affected throughout this time period and even beyond this time period due to delayed withdrawal effects once all cannabis compounds have been fully cleared from the brain and body.

Modern medical and recreational cannabis dispensaries commonly offer specialized strains of cannabis that may be enriched for various components of the cannabis plant, such as cannabidiol. Cannabidiol (CBD) has been found to act on the GABA system in the brain and has effects similar to prescription sleeping and antianxiety medications (such as Valium, Ativan and Ambien). As with prescription sleeping medications, tolerance to CBD develops over time, meaning that the sedating effects of CBD will wane with prolonged usage. Sleeping medications are generally no longer recommended for the long-term treatment of insomnia and therefore long-term use of CBD is not recommended for the treatment of insomnia.

Recommendations:

• Cannabis is not recommended as a nightly sleep aid at this time due to a very long duration of action (meaning you will be sedated during the day), the potential to actually worsen sleep disturbances over time, and unproven benefits.

Sources:

• https://www.medscape.org/viewarticle/497982
• https://www.huffingtonpost.com/2015/03/05/how-smoking-affects-sleep_n_6792954.html
• https://www.uptodate.com/contents/e-cigarettes?search=nicotine&source=search_result&selectedTitle=8~150&usage_type=default&display_rank=8
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