Acute effects of water-pipe smoking on pulmonary function and cardio-pulmonary exercise capacity in healthy subjects

Background: Waterpipe tobacco smoking (WTS) has gained popularity, but the physiologic effects of WTS have not been extensively studied. Studies that have evaluated the impact of WTS have focused on its chronic effects or have only evaluated limited parameters. In a pilot study, we evaluated the acute effects of WTS on lung function and exercise capacity in water-pipe users. We hypothesized that acute exposure to WTS alters pulmonary function and cardio-pulmonary exercise test (CPET) responses. Methods: We recruited 15 healthy WTS male subjects (S). We used a single-group pre-test (having abstained from WTS for at least 48 hours before testing) post-test (within half an hour of 45-minute WTS session in a cafe design). We performed spirometry and CPET (cycloergometer; 2-min 20-Watt warm-up and 25-Watt increase every 2-min for 10 min). Results: Mean age was 21.2 years; average carbon monoxide pre-test was 4.6 ppm and 27.5 ppm post-test; forced expiratory volume in one second (FEV1) decreased in 7/15 S by 0.48 L/sec (9%), forced expiratory flow from 25% to 75% of vital capacity (FEF25-75%) decreased in 11/15 S by 0.65 L/sec (12%). Breathing reserve decreased in 10/15 S by 10.2%; oxygen pulse decreased in 9/15 S by 2.4 mL/beat (19%); 8/15 S could not complete the CPET after WTS (8.29 min average), vs. 6/15 S pre-WTS (8.33 min average); 9/15 S reported greater degree of shortness of breath at mid/peak exercise using Borg scale; among those completing exercise time pre and post (6/15 S), maximum oxygen consumption (VO2max) dropped in 5/6 S. Conclusion: Acute WTS causes impairment in pulmonary function and CPET ventilatory and cardiovascular responses.