Nicotine’s Impact on Sleep
As nicotine is a stimulant, it is no surprise that its consumption, especially close to bedtime can disturb sleep. Nicotine attaches to nicotinic cholinergic receptors (NAChRs), which triggers the release of feel-good neurotransmitters including serotonin, dopamine, glutamate and gamma aminobutyric acid — making it both stimulating and addictive.
Nicotine is known to significantly increase the activity in the prefrontal cortex, thalamus, and visual system. Additionally, it stimulates the nervous system and a 2013 study provided evidence that cigarette smoke from traditional tobacco products may lead to dysregulation in circadian rhythms, which may impact smokers’ sleep/wake cycles, and contribute to higher levels of insomnia and earlier wake times.
Smoking and Sleep-Related Disturbances
A 2020 Canadian study found that smokers are 47% more likely to experience sleep-related issues than nonsmokers, concluding a correlation between depression and other comorbidities that can affect sleep. Similarly, according to a 2021 study on night-time smoking habits and insomnia from self-reported information gathered from over 1,000 adults ages 22 to 60, smokers experienced increased insomnia and very short sleep compared to nonsmokers. Additionally, the results suggested that insomnia and decreased sleep durations were intensified by smoking later at night.
The use of tobacco products has also proven to affect both the macro- and microstructure of sleep. A study conducted in Lausanne, Switzerland based on a cross-sectional analysis of sleep characteristics in smokers, former smokers, and nonsmokers measured sleep macrostructure through the use of polysomnography (PSG) tests and examined sleep microstructure of sleep by analyzing the electroencephalogram (EEG) data. Smoking intensity showed a dose-dependent association with faster EEG activity including less delta-wave activity (a maker of sleep depth) and an increase in alpha-wave power (associated with arousal).
Attenuating Insomnia From Nicotine Withdrawal
Not only is insomnia related to smoking, it can also be exacerbated by nicotine withdrawal. Inversely, the withdrawal symptoms of smoking cessation are shown to be aggravated by insomnia, creating a vicious cycle, which makes the difficult process of abstaining from a highly addictive substance even more challenging. Thankfully, there are a few promising therapies that have been shown to help decrease insomnia symptoms caused by nicotine withdrawal such as cognitive-behavioral therapy for insomnia (CBT-I) and exercise.
A 2014 study on CBT-I demonstrated that it may improve smoking cessation outcomes in smokers when paired with traditional smoking cessation therapy. Additionally, exercise may reduce smoking cravings and improve nicotine withdrawal symptoms. We know that exercise improves insomnia in the general population; however less research exists on the effect of exercise on insomnia within the smoking population. A 2018 study examining the relationship between sleep, smoking and exercise analyzed the impact of exercise on those who smoked. Data on sleep quality was collected using the Insomnia Severity Index (ISI) and the Pittsburgh Sleep Quality Index (PSQI). Smoking information was collected utilizing the Fagerstrom Test for Nicotine Dependence, Minnesota Nicotine and Withdrawal Scale, and Questionnaire of Smoking Urges. Overall, results indicated that poorer sleep quality was associated with greater withdrawal and cravings.
For the exercise component, the study placed smoking patients in a 12-week exercise program that included three 30-minute exercise sessions per week and measured levels of insomnia during and after the program. Results showed that an increase in exercise was associated with better sleep.
Nicotine use and abuse are associated with an increase in sleep disturbances compared to the general population. This includes the use of traditional tobacco products and vaping. Nicotine withdrawal exacerbates insomnia which only complicates the process of quitting. However, there is promising research that both CBT-I and exercise may reduce insomnia related to nicotine withdrawal in smokers looking to quit.