Introduction:
Waterpipe smoking is characterized by long sessions of smoking, deep inhalation of tobacco smoke, and longer puffs compared to cigarette smoking. Clearly, waterpipe smokers are exposed to high levels of tobacco smoke. Waterpipe smoke contains carcinogens and toxicants, such as tobacco-specific nitrosamines, benzene, nitric oxide and heavy metals. Nicotine impact on hemodynamic responses is evident by increase in heart rate, constriction in blood vessels, and increase in myocardial contraction which contribute to acute cardiovascular events.

Methods:
This secondary analysis was completed using data from a randomized clinical trial to investigate the direct effects of nicotine (published elsewhere). Twenty-four young adults smoked waterpipe tobacco for 45 minutes in a controlled environment once a week for 4 weeks. Carbon Monoxide was measured pre and post smoking. Heart rate was measured continuously during smoking. The two nicotine conditions were placebo and nicotine tobacco.

Results:
Heart rate increased significantly over time while smoking nicotine containing waterpipe tobacco. The mean heart rate increased from 78 ± 12 (at baseline) to 86 ± 13 (post smoking) in the nicotine condition and from 72 ± 11 (baseline) to 77 ± 9 (post smoking) in the non-nicotine condition. CO levels increased significantly from pre smoking (1.18 ± 1.05) to post smoking (16.83 ± 12.45) in the nicotine condition and the increase was significant (t = 6.18, p <.00). Also, CO levels increased from pre smoking (1.27 ± .93) to post smoking (19.62 ± 12.64) in the non-nicotine condition and the increase was significant (t = 6.89, p <.00).

Funding:
Washington State University Alcohol and Drug Abuse Research Program.