You probably already know that smoking is bad for you, but a new study shows that smoking first thing in the morning is apparently even worse. Among the 7,610 smokers studied—62% of whom had lung cancer—those who lit up within 30 minutes of waking were 79% more likely to have developed lung cancer than smokers who held off for an hour or more after waking, reports the BBC.
Researchers say the effect is independent of other smoking habits, and speculate that those who smoke early in the day might smoke “more intensively” and inhale more smoke into their lungs. A different study of 1,850 smokers, 57% of whom had head or neck cancer, found that those who smoke within a half-hour of waking were 59% more likely to have developed a tumor, though the authors aren’t sure why. In that study as well, waiting at least an hour seemed to have a benefit.