The acute effects of waterpipe smoking on lung function and exercise capacity in a pilot study of healthy participants

Smoking waterpipe (WP) is a social habit that has been spreading across the globe. Although classically known in the Middle East and other eastern countries, recent statistics show that western countries are now part of this new ‘trendy’ way of using tobacco. Many factors have been contributing to the spread of WP use, including myths and misconceptions regarding its harms.

Recently, the body of evidence has been mounting with regards to the harmful effects of WP, linking its use to the development of many diseases such as cancer, cardiovascular, and respiratory illnesses. However, since the use of WP is considered a component of social settings, many regard it as a harmless practice that can be undertaken on occasions without inflicting harm on its user. Such a perception has been driving the spread of WP especially among the youth.

We examined the acute effects of WP smoking on lung function and exercise capacity in healthy participants to shed light on the harms of this practice (The acute effects of waterpipe smoking on lung function and exercise capacity in a pilot study of healthy participants. Inhalation Toxicology August 2013). The study explored the effect of a single 45-minute session of WP smoking on the lung function and the exercise capacity of young healthy volunteers. Regular WP smokers were asked to abstain for 48 hours, and a baseline pulmonary function test (PFT) and a cardiopulmonary exercise test (CPET) were performed. Subjects rested for few days and the PFT and CPET tests were performed again after a 45-minute single session of WP smoking. The acute rise in CO as a result of the WP session was confirmed (CO levels post WP smoking were 24.4 ppm, while in the baseline session levels were 3.7ppm). This sharp rise was most likely responsible for the majority of the detrimental outcomes we observed in our study.

Compared to their baseline measures, subjects felt more exhausted performing the same level of exercise (as measured by the Borg scale) after the WP session. Baseline systolic blood pressure, pulse pressure, and pulse pressure products all increased. Furthermore, there was a significant drop in oxygen consumption by the muscles across participants, including those who could complete the same exercise time before and after smoking WP. Oxygen consumption (VO2) decreased from 1.86 to 1.7 (L/min). This drop was associated with a drop in oxygen pulse ( O2 pulse dropped from 10.89 to  9.97 ml/beat) and a higher heart rate to cope with the same level of work performed by the muscles (HR/VO2 at peak increased from 3.52 to 3.91beats/ml/Kg). It is likely that all such changes are due to the high CO levels resulting from WP smoking and the failure of normal vasodilatation to the exercising muscle, as indicated by the increase in systolic blood pressure (SBP) detected after smoking WP. With regards to lung function testing, acute exposure to WP smoke was associated with the development of acute small airway obstruction as shown by the drop in FEF 25-75% from 5.51L to 5.29L.

Such characterizing contributes towards a more comprehensive understanding of the impact of WP smoking on critical physiological measures, and provides talking points that can serve as a deterrent when counseling youth against this deceivingly harmless practice. Thus, the results of the study will be used to inform healthcare professionals and WP users about the harms of occasional WP use. Such evidence can also motivate the youth and specifically those involved in athletic activities to avoid smoking WP which can negatively impact their performance.

About the Author: Feras I Hawari, MD, is the Regional Director for Global Bridges in the Eastern Mediterranean Region. He is the Director of the Cancer Control Office at King Hussein Cancer Center, in addition to his other duties as Chief of Pulmonary and Critical Care Service and Director of the Respiratory Unit.