Smoking within first 30mins of waking up, chances increased by 79 per cent
Having a cigarette first thing in the morning can increase your chances of developing cancer, according to US researchers.
Cancer Research UK suggested that people who were quick to smoke may inhale more into their lungs.
The study of 7,610 smokers, published in the journal Cancer, says that the effect is independent of other smoking habits.
Having a cigarette within the first 30 minutes of waking up nearly doubled the risk of lung cancer - which is already at an alarming risk.
Scientists at the Penn State College of Medicine in the US looked at 4,776 smokers with lung cancer and 2,835 smokers without cancer.
The results indicated that the patients who smoked 30 minutes after waking up were 79 per cent more likely to develop cancer than those who waited an hour.
Cancer Research UK's Professor Robert West told the BBC: "Smokers who light up soon after waking tend to smoke each cigarette more intensively.
"So the most likely explanation of this findings is that the sooner a smoker lights up, the more smoke is taken into the lungs, and the higher level of exposure to cancer causing chemicals.
"This may help estimating levels of tobacco exposure more than just looking at the usual daily cigarette consumption."
Taryn Davies