Professor Christina Gratziou, one of the authors and Chair of the ERS Tobacco Control Committee, said: "We do not yet know whether unapproved nicotine delivery products, such as e-cigarettes, are safer than normal cigarettes, despite marketing claims that they are less harmful.
This research helps us to understand how these products could be potentially harmful.
"We found an immediate rise in airway resistance in our group of participants, which suggests e-cigarettes can cause immediate harm after smoking the device.
More research is needed to understand whether this harm also has lasting effects in the long-term.
recommends following effective smoking cessation treatment guidelines based on clinical evidence which do not advocate the use of such products," Professor Gratziou