Electronic cigarettes have steadily grown in popularity but little is still known about the effects using the vapor has on health. Researchers, however, found that just one use has the ability to reduce cough reflex sensitivity, with a single exposure equivalent to enough nicotine in one tobacco cigarette.

For a study published in the journal CHEST, researchers worked with 30 adults who are lifetime nonsmokers and who don't have histories of respiratory disease or asthma, utilizing cough tests to gauge how e-cigarettes can affect cough reflex sensitivity.

Using capsaicin, or red pepper extract, the researchers induced safe coughs in the subjects, establishing baseline cough reflex sensitivity for each. All subjects were then given e-cigarettes and instructed to take 30 puffs. After 15 minutes of using an e-cigarette, each subject was tested again for cough reflex sensitivity. The test was repeated after 24 hours.

Based on results, the subjects exhibited a dramatic decrease in cough reflex sensitivity after using e-cigarettes when comparing baseline figures and results of the subsequent tests.

According to the researchers, it's probably nicotine that was responsible for lowering cough reflex sensitivity. Prior research has shown that the compound can also cause a cough immediately after being ingested, suggesting that nicotine functions in two ways: as an immediate cough reflex stimulant and as a delayed inhibitor.

Cough reflex sensitivity is important because coughing is a way for the body to protect its airways from the adverse effects of having inhaled irritating or noxious substances. Because it is a protective reflex, coughing, especially the persistent kind, is considered a major symptom of respiratory disease.

The cough reflex is made up of five components: cough receptors; afferent nerves; a poorly defined cough center; efferent nerves; and effector muscles. Cough receptors are located throughout the airway and the upper gastrointestinal tract, as well as the diaphragm and pericardium.

It is possible for a cough to be voluntarily initiated but it will not have the same pressure and force as one that was triggered by cough reflex. When a cough is triggered, up to 2.5 liters of air fill the lungs. When enough pressure is reached, all that air is released in an explosive manner. This explosive manner is what makes it possible for the body to expel the irritating or noxious substance inhaled.

Photo: Ecig Click | Flickr