Scientists have discovered another potential health hazard of smoking - an increased risk of frostbite.
Frostbite can be a serious problem
A team from Yale University found that smoker's blood vessels do not expand fast enough to warm chillled fingers and toes.
They believe nicotine slows the body's normal response to cold. Smoking is already known to cause problems with blood circulation.
The research was presented at a meeting of the American Physiological Society.
The researchers immersed the hands of smokers and non-smokers in water at 5C for 40 minutes.
After coming out of the water, the smoker's skin warmed up more slowly.
The same effect was observed even after smokers have refrained from the habit for 16 hours.
Eric Pirie, a course director at the Wilderness Emergency Medical Services Institute, said he advised people who were venturing out into inhospitable conditions not to smoke.
"We would certainly say to them that medical opinion is that peripheral circulation tends to be les good if you smoke," he said.
A spokesperson for the anti-smoking charity Action on Smoking and Health said: "Smoking causes blood vessels to contract increasing the risks of heart attacks, strokes and a number of diseases linked to poor circulation.
"That smokers are more susceptible to frostbite in severe conditions is just an extension of this nicotine related phenomenon "
Simon Clark, director the smoker's rights group Forest, said: "If it's true, and I suspect that the risk is statistically insignificant, it will be interesting to see whether smokers have a case against governments and local authorities who ban smoking in enclosed public places.
"After all, if they are putting smokers at risk by forcing them to stand outside in the freezing cold they may have to suffer the consequences."
Frostbite is the literally the freezing of the skin and/or the tissues under its surface. This can cause tissue damage, which can be so severe that amputation is the only answer.