Smoking cigarettes at night shows a stronger link to poor sleep than does smoking at earlier times in the day, according to a new study. To help patients, sleep hygiene should be considered and incorporated into smoking-cessation efforts, researchers write in the journal Sleep Health. "While many people smoke to relax, nicotine is a stimulant. For this reason, people who smoke - especially at night - have worse insomnia and are more likely to get insufficient amounts of sleep," said Dr. Michael Grandner of the University of Arizona College of Medicine in Tucson. Poor sleep is linked with a variety of health issues, he and his coauthors write, and insomnia is related to higher healthcare costs, lost workdays and major health consequences. "Insomnia and sleep loss lead to increased stress and could lead to more smoking," Dr. Grandner told Reuters Health by email. "So you really have a perfect storm of poor sleep and smoking." Dr. Grandner and colleagues analyzed data from the Sleep and Healthy Activity Diet Environment and Socialization study, which included more than 1,000 adults between ages 22-60 in Philadelphia between 2012 and 2014. The team looked at self-reported smoking status for cigarettes and other tobacco products, the timing of smoking, insomnia severity and sleep duration. Smokers had 2.5 times higher odds of experiencing moderate-to-severe insomnia than non-smokers (P<0.001). Smoking was also associated with 3.3-fold higher odds of a "very short" sleep duration of four hours or less, also a significant risk increase, as well as a higher risk of "short" sleep duration of five or six hours. Night-time smoking, in particular, was significantly associated with greater insomnia and shorter sleep. Smoking between 11 p.m. and 2 a.m. was linked with a significant 2.4-fold increase in the odds of experiencing more severe insomnia. Late-night smoking, from 2 a.m. to 5 a.m., was also associated with 2.5-fold higher odds of severe insomnia. In terms of sleep duration, smoking between 11 p.m. and 2 a.m. had the highest likelihood of short sleep versus normal sleep. "The thing that was surprising was that it wasn't just the long-term effects of smoking that were bad for sleep health, but likely the short-term stimulant effects of the nicotine itself," Dr. Grandner said. "Maybe people are more likely to smoke at night because they had worse sleep in the first place . . . I look forward to exploring that in the future." Future research could better investigate the timing of smoking and sleep, the authors write, and untangle the complex relationship between the two. Clinicians and researchers should consider how smoking status affects sleep, especially when planning smoking-cessation programs. If smokers can change the timing or amount of nicotine intake around bedtime, they may be more likely to get better sleep, which can help them to quit smoking as well. "Considering how important sleep is for physical and mental health, research surrounding ways to optimize sleep can have far reaching public health implications," said Dr. Christine Spadola of the Florida Atlantic University College of Social Work and Criminal Justice in Boca Raton. Dr. Spadola, who wasn't involved with this study, has researched nighttime nicotine use and sleep duration. She and colleagues found that smoking within four hours of bedtime was associated with a 48-minute reduction in sleep time. "It can be extremely difficult to quit smoking," she told Reuters Health by email. "If smoking cessation is not possible, guidance surrounding ways to time nicotine use to alleviate the negative impact on sleep can be useful." —Carolyn Crist Source
