Why smoke fewer cigarettes?

Sixteen volunteers were tested when smoking their own brand of cigarettes normally and when smoking half their usual number of cigarettes. While smoking half their usual amount the subjects changed their inhalation behaviour. Over this period the percentages of carboxyhaemoglobin were not significantly different from steady-state values where plasma nicotine concentration rose significantly. With the reduction in cigarettes there were significant falls in haemoglobin concentration, packed cell volume, and red cell count. These findings suggest that the advice given to patients to smoke fewer cigarettes should be accompanied by a warning against increasing inhalation. Patients who say that they have reduced their smoking but who have unaltered carboxyhaemoglobin concentrations should not be discredited.