Smoking is linked to shorter, lighter and more fragmented sleep. Nicotine stimulates the nervous system and may make it harder to fall asleep. It can reduce deep sleep, while falling nicotine levels overnight may cause cravings, restlessness and waking. Smoking also irritates the upper airway and raises the risk of sleep apnea.
A systematic review discussed below included six cohort studies involving 12,445 participants.
At a Glance
| Effect of smoking | What may happen during sleep |
|---|---|
| Nicotine stimulation | Trouble falling asleep or feeling "wired" |
| Overnight nicotine withdrawal | Waking, restlessness and early-morning cravings |
| Sleep disruption | More time awake after falling asleep and less restorative sleep |
| Reduced deep sleep | More light sleep and less slow-wave sleep |
| Airway irritation | Higher risk of snoring and obstructive sleep apnea |
| Poor-quality sleep | Daytime tiredness, poor concentration and irritability |
Why Does Nicotine Interfere With Sleep?
Nicotine is a stimulant. Smoking close to bedtime can increase alertness and delay sleep onset.
Research on chronic tobacco use has found that smokers may spend more time awake after falling asleep, get more light sleep and spend less time in slow-wave, or deep, sleep than nonsmokers. These changes can happen even when a smoker does not describe their sleep as severely disturbed.
Nicotine also acts for a relatively short time. As nicotine levels fall during the night, people who are dependent on nicotine may experience withdrawal. That can bring restlessness, cravings, lighter sleep or waking up to smoke.
Smoking may seem to relieve the discomfort for a while, but nicotine dependence can help keep the cycle going. The cigarette eases the withdrawal. The withdrawal then disrupts sleep again.
Does Smoking Cause Insomnia?
Smoking is associated with a higher risk of insomnia, but it does not cause insomnia in every smoker. A systematic review of six cohort studies involving 12,445 participants found that regular smoking was associated with a small increase in the later development of insomnia. The researchers also said that the available evidence was limited and that more high-quality studies are needed.
Smoking-related sleep problems may include:
- Taking longer to fall asleep
- Waking repeatedly during the night
- Waking too early
- Finding it hard to return to sleep
- Feeling unrefreshed despite spending enough time in bed
Stress, depression, anxiety, alcohol, caffeine and other health conditions can affect sleep too. Smoking may be one factor rather than the only cause.
Can Smoking Increase Sleep Apnea Risk?
Yes. Smoking can raise the risk of sleep apnea. The National Heart, Lung, and Blood Institute says that smoking can inflame the upper airway and interfere with breathing during sleep. It also lists smoking as a lifestyle factor that increases sleep apnea risk.
Possible warning signs include:
- Loud or persistent snoring
- Gasping, choking or pauses in breathing during sleep
- Morning headaches
- Dry mouth on waking
- Excessive daytime sleepiness
- Difficulty concentrating
Untreated sleep apnea can affect blood pressure, cardiovascular health and daytime alertness. Breathing pauses or severe daytime sleepiness are reasons to speak with a healthcare professional about an evaluation.
Does Smoking Before Bed Make Sleep Worse?
Smoking before bed is unlikely to improve sleep and may make it harder to fall asleep or stay asleep. The closer smoking occurs to bedtime, the more likely nicotine's immediate stimulant effects are to overlap with the normal sleep period. Later, the drop in nicotine levels can cause withdrawal-related waking.
Avoiding a cigarette before bed may reduce immediate nicotine stimulation, but changing the timing does not remove the effects of tobacco dependence. Quitting smoking is the most effective long-term way to remove smoking-related sleep risks.
What Happens to Sleep After Quitting Smoking?
Sleep may get worse for a short time after quitting. Nicotine withdrawal commonly includes difficulty sleeping, vivid dreams, restlessness and changes in sleep duration. These symptoms usually reflect withdrawal. They do not mean that smoking was helping you sleep.
Nicotine replacement therapy can affect sleep for some people. The CDC notes that nicotine patches may interfere with sleep and advises discussing patch timing or other options with a healthcare professional. Do not change prescribed medicines without professional advice.
A practical approach is to:
- Use an evidence-based quit-smoking treatment plan.
- Expect some short-term sleep disruption.
- Keep a consistent wake-up time.
- Avoid caffeine later in the day, especially because caffeine can remain in the body longer after quitting.
- Ask a healthcare professional if insomnia continues or becomes severe.
- Seek support from a clinician, pharmacist or quit-smoking service.
Can Secondhand Smoke Affect Sleep?
Secondhand smoke is also associated with sleep problems. A systematic review involving more than 730,000 participants found modest associations between secondhand smoke exposure and short sleep duration, excessive daytime sleepiness and poor sleep quality.
The studies were observational, and many relied on self-reported exposure. The findings show an association, not proof that secondhand smoke directly caused each sleep problem.
Bottom Line
Smoking can affect both sleep quality and breathing during sleep. Temporary insomnia after quitting is common, but it does not mean cigarettes were improving sleep. Persistent insomnia, breathing pauses, gasping during sleep or severe daytime sleepiness warrant medical advice.