As if all their other problems weren't enough, a new study indicates that beleaguered smokers tend to get less sleep and are at higher risk of serious insomnia. Researchers in Germany surveyed around 1,100 smokers and 1,200 non-smokers—all of whom were pronounced free of mental health conditions that might impair sleep—for a study published in the Addiction journal. They found that 17% of smokers slept for less than six hours a night, compared with just seven percent of non-smokers. And 28% of the smokers claimed to have “disturbed” sleep, against 19% of smoke-free sleepers. "If you smoke and you do suffer from sleep problems, it is another good reason to quit smoking," says lead researcher Dr. Stefan Cohrs, of Charite Berlin medical school. Grounds for optimism? Cors adds that past research shows that a smoker's sleep quality does improve after quitting. The study doesn't yet prove that smoking alone impairs sleep, but researchers believe the stimulating effects of nicotine play a part, as well as the possibility that smokers may be more likely to have other habits that affect sleep—such as getting little exercise or staying up late to watch TV. It seems smokers can't win: successfully losing consciousness reportedly puts them at risk of manifesting a violent sleep disorder, while inadequate sleep has been linked to problems like diabetes, heart disease and obesity.