Nicotine is a stimulant, and in a polysomnography study of 6,400 adults, current smokers took 5.4 minutes longer to fall asleep, slept 14.0 minutes less and had less slow-wave sleep than never smokers, while former smokers did not differ from never smokers. A review of 52 studies found the same direction (more fragmentation, less deep sleep, suppressed REM) and a meta-analysis of prospective studies put the risk ratio for sleep-related problems in smokers at 1.47. Caffeine and alcohol disturb sleep in different ways. This page summarizes studies; it does not give quitting advice.
What is the link between nicotine and sleep? Nicotine is a stimulant, and studies of smokers find slower sleep onset, less deep sleep and more broken nights than in never smokers. The differences are small in minutes and consistent in direction.
This page compares what the research shows for nicotine, with the better-known caffeine and alcohol findings next to it. It is a study overview and not advice about quitting, which is a decision to plan with a doctor or a cessation service. If you are looking at alcohol in detail, insomnia after quitting drinking covers it, and sleep hygiene tips covers the general habits.
Nicotine and sleep: what the large studies show
The biggest objective data come from the Sleep Heart Health Study. Polysomnography was used to characterize sleep architecture among 6,400 participants (2,916 never smokers, 2,705 former smokers and 779 current smokers). Compared with never smokers, current smokers had a longer initial sleep latency (5.4 minutes, 95% CI 2.9 to 7.9) and less total sleep time (14.0 minutes, 95% CI 6.4 to 21.7), more stage 1 sleep (relative proportion 1.24) and less slow-wave sleep (0.86). Former smokers and never smokers did not differ. The authors concluded that cigarette smoking is independently associated with disturbed sleep architecture, with a shift toward lighter stages, and that nicotine and acute withdrawal from it may contribute.
Zhang L, Samet J, Caffo B, et al. Cigarette smoking and nocturnal sleep architecture. Am J Epidemiol 2006. PMID 16829553
A questionnaire study of 3,516 adults, part of an epidemiologic study of sleep-disordered breathing, found smoking associated with difficulty initiating sleep and difficulty waking up in men and women, with daytime sleepiness related to smoking in women and disturbing dreams in men. Its authors suggested the stimulant effect of nicotine, nightly withdrawal, more sleep-disordered breathing and psychological factors as possible explanations.
Wetter DW, Young TB. The relation between cigarette smoking and sleep disturbance. Prev Med 1994. PMID 8078854
A pooled analysis of prospective studies gives the long view: smoking was associated with a risk of developing sleep-related issues (risk ratio 1.47, 95% CI 1.20 to 1.79), though the authors found publication bias in the data.
Amiri S, Behnezhad S. Smoking and risk of sleep-related issues: a systematic review and meta-analysis of prospective studies. Can J Public Health 2020. PMID 32185746
What nicotine does to sleep stages
A descriptive review of 52 studies (animal and human) on nicotine consumption, withdrawal and replacement therapy summarized the sleep findings during consumption: increased sleep latency, sleep fragmentation, decreased slow wave sleep with reduced sleep efficiency, and increased daytime sleepiness. Most studies also indicated nicotine-induced REM sleep suppression. The review adds that smoking was associated with more sleep-related respiratory disorders, and that findings were partly inconsistent because of different methods. It also notes that the effects of therapeutic nicotine substitution after quitting were often masked by withdrawal symptoms; this page does not discuss products or give advice on them.
Jaehne A, Loessl B, Bárkai Z, et al. Effects of nicotine on sleep during consumption, withdrawal and replacement therapy. Sleep Med Rev 2009. PMID 19345124
So nicotine and sleep stages is a story of lighter sleep, with REM and deep sleep trimmed. For the meaning of those stages, see deep sleep vs REM sleep.
Waking at night: withdrawal and night smoking
Nicotine levels fall over the night, and withdrawal is one proposed reason for waking. Researchers have looked at people who wake to smoke. In a pre-cessation analysis of 385 smokers who filled in the Pittsburgh Sleep Quality Index and a question on waking at night to smoke, night smokers reported significantly more sleep disturbance than non-night smokers, and those with both night smoking and sleep disturbance were at higher risk of failing to quit in the trial than smokers with neither. The trial itself tested a medicine and a patch, which this page leaves aside. The authors read night smoking as an indicator of nicotine dependence.
Peters EN, Fucito LM, Novosad C, et al. Effect of night smoking, sleep disturbance, and their co-occurrence on smoking outcomes. Psychol Addict Behav 2011. PMID 21443301
What happens to sleep after someone stops is the subject of a 2025 systematic review. It compared sleep before and after smoking cessation, and between people who stayed abstinent and people who relapsed. In people quitting without nicotine replacement, the share of stage 1 sleep fell in those who stayed abstinent for 6 months, REM sleep was reduced only in those who relapsed, and slow-wave sleep did not differ significantly between the two groups. The results were heterogeneous, and the authors concluded that sleep alterations appear to persist for the first few weeks of withdrawal and predict relapse.
Mauries S, Rolland B, Mallevays M, et al. Conditions of sleep restoration after smoking cessation: A systematic review. Sleep Med Rev 2025. PMID 39893864
The practical reading is cautious. Sleep during the first weeks of withdrawal is a documented difficulty, not a sign that something is going wrong, and the studies describe groups rather than predicting any one person. This is one reason tracking sleep through a change is useful. How to manage it belongs with a doctor or a cessation service, and nothing on this page replaces that conversation.
Vaping and sleep
E-cigarettes deliver nicotine without smoke, and the survey data look similar. In US adults in the 2015 to 2018 national health survey (11,659 people), current e-cigarette use was associated with higher odds of trouble sleeping (odds ratio 2.16, 95% CI 1.49 to 3.13) compared with never use, and former e-cigarette use also (1.54). Current cigarette use went with short sleep (1.65) and trouble sleeping (1.36), and current dual users had odds of 1.64 for short sleep and 2.14 for trouble sleeping. Cross-sectional data like these cannot say which came first, and people who vape often smoke or have smoked.
Wang S, Nandy RR, Rossheim ME. Associations between e-cigarette use and sleep health among adults in the United States, NHANES 2015-2018. Sleep Med 2024. PMID 38232605
Caffeine and sleep, and alcohol and sleep, side by side
Caffeine and sleep are better quantified than nicotine and sleep. A systematic review and meta-analysis of 24 studies found that caffeine reduced total sleep time by 45 minutes and sleep efficiency by 7%, increased sleep onset latency by 9 minutes and wake after sleep onset by 12 minutes, and cut deep sleep by 11.4 minutes. In a home study, a fixed 400 mg dose of caffeine taken 0, 3 or 6 hours before habitual bedtime each disturbed sleep compared with placebo, with the 6-hour condition still showing an important reduction in total sleep time.
Gardiner C, Weakley J, Burke LM, et al. The effect of caffeine on subsequent sleep: A systematic review and meta-analysis. Sleep Med Rev 2023. PMID 36870101
Drake C, Roehrs T, Shambroom J, et al. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med 2013. PMID 24235903
An earlier systematic review of epidemiological studies and randomized trials reached the same direction: caffeine typically prolonged sleep latency, reduced total sleep time and sleep efficiency and worsened perceived sleep quality, and slow-wave sleep was typically reduced. The sleep of older adults may be more sensitive to caffeine, and individual differences are pronounced, with genes involved in adenosine signaling and metabolism contributing to sensitivity. Most of the studies were in male adults from Western countries, which limits how far the findings generalize.
Clark I, Landolt HP. Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials. Sleep Med Rev 2017. PMID 26899133
Alcohol works differently. A meta-analysis of 27 studies in healthy adults found that alcohol delayed and reduced REM sleep, with disruption seen even after a low dose (about two standard drinks) and getting worse with dose, while shorter sleep onset latency appeared only after a high dose (about five standard drinks). The effects on total sleep time, efficiency and wake after sleep onset could not be determined.
Gardiner C, Weakley J, Burke LM, et al. The effect of alcohol on subsequent sleep in healthy adults: A systematic review and meta-analysis. Sleep Med Rev 2025. PMID 39631226
| Substance | Main sleep findings in studies | Study and size |
|---|---|---|
| Nicotine (smoking) | Longer time to fall asleep (5.4 minutes), 14.0 minutes less sleep, more light sleep, less slow-wave sleep; former smokers did not differ | Polysomnography, 6,400 adults |
| Nicotine (review) | Increased latency, fragmentation, reduced slow-wave sleep and efficiency, REM suppression | Review of 52 studies |
| Caffeine | 45 minutes less total sleep time, 7% lower efficiency, 9 minutes longer to fall asleep, 12 minutes more waking | Meta-analysis, 24 studies |
| Alcohol | Later and shorter REM sleep from about two drinks; shorter latency only at about five drinks | Meta-analysis, 27 studies |
In short, each of the three is a different kind of sleep disruptor: nicotine and caffeine act as stimulants, alcohol as a sedative that trims REM. The studies do not tell you how they combine in one evening.
Is nicotine linked to sleep apnea?
A meta-analysis of 14 observational studies asked whether obstructive sleep apnea is associated with alcohol, caffeine or tobacco use. It found no association with tobacco, a positive association with alcohol (odds ratio 1.33, 95% CI 1.10 to 1.62) and insufficient data for caffeine, and the overall quality of the evidence was low to very low. The sleep-disordered breathing finding in the questionnaire study above points the other way, which is a reminder that the data are mixed. Loud snoring with pauses in breathing is a reason to be tested whatever the cause; is snoring bad explains what to look for.
Taveira KVM, Kuntze MM, Berretta F, et al. Association between obstructive sleep apnea and alcohol, caffeine and tobacco: A meta-analysis. J Oral Rehabil 2018. PMID 29971810
What SleepTrace can show, and what it cannot
SleepTrace cannot detect nicotine, caffeine or alcohol, and it does not know when you last smoked or vaped. It listens through the microphone of your iPhone or Android phone, sound only. It can show the nightly sleep score and trends, so you can compare a few weeks before and after a change in your own habits, and sleep phases estimated from sound (read them as estimates). If you cough or snore at night, the app stores playable clips with a dB peak and a time, and possible breathing pauses appear as timestamps without a clip.
The free plan covers nightly tracking and 3 playable clips a month. Keep the app open (the screen dims by itself) and the phone on its charger. Whether to cut down or stop is a question for you and a doctor or a cessation service; the app is only a record of how your nights go meanwhile.
Frequently asked questions
Nicotine is a stimulant, and the studies show lighter, more broken sleep in smokers. In a polysomnography study of 6,400 adults, current smokers had a longer time to fall asleep (5.4 minutes), less total sleep time (14.0 minutes), more stage 1 sleep and less slow-wave sleep than never smokers. A review of 52 studies also found REM sleep suppression during nicotine use.
Withdrawal is the explanation most often proposed. A 1994 survey of 3,516 adults found smoking associated with difficulty initiating sleep and a constellation of symptoms suggestive of sleep fragmentation, and its authors listed nicotine's stimulant effect and nightly withdrawal as possible reasons. Among 385 smokers, those who woke at night to smoke reported significantly more sleep disturbance than those who did not.
Associations are similar. In US adults from the 2015 to 2018 national survey (11,659 people), current e-cigarette use was associated with higher odds of trouble sleeping (odds ratio 2.16) and former use also (1.54). The survey is cross-sectional, mixes dual users with exclusive vapers, and cannot show that vaping caused the problems.
In the 6,400-person polysomnography study, former smokers did not differ from never smokers in sleep architecture, which the authors interpreted as the changes being tied to current smoking and acute withdrawal. That was a snapshot, not a follow-up of individuals through quitting. The review above reports sleep impairment during withdrawal, so a doctor or cessation service is the right place to plan a change.
Both are stimulants, but the caffeine evidence is more quantified. A meta-analysis of 24 studies found caffeine reduced total sleep time by 45 minutes and sleep efficiency by 7% and increased sleep onset latency by 9 minutes. A 400 mg dose taken 6 hours before bedtime still disrupted sleep in a home study, so timing during the day matters for it as well.
Not in the best available pooled data. A meta-analysis of 14 observational studies found no association between obstructive sleep apnea and tobacco, a positive one with alcohol (odds ratio 1.33), and too little data for caffeine; the quality of the evidence was low to very low.
SleepTrace is a wellness app, not a medical device. This article is general information, not medical advice. If your symptoms are frequent, severe or worrying, please talk to a doctor.
If you want to know what nicotine does to your nights, compare them. SleepTrace tracks each night from sound, estimates sleep phases and shows the trend across weeks, so a change in your habit becomes visible, and coughing and snoring are saved as playable clips with a time. It does not know when you smoked or vaped, so you keep track of that yourself.
Hear your own night. SleepTrace turns a night of audio into your sleep phases, the sounds you made, and how it all trends. Works without a wearable, better with one. Your phone on the nightstand is enough to start. Get it for iPhone or Android →