The short-term effect of water-pipe smoking on the baroreflex control of heart rate in normotensives
Introduction
Tobacco is one of the major preventable causes of death in developed and developing countries. Every day over 13,000 people worldwide die from tobacco, i.e. 5 million every year (WHO, 2004).
Water-pipe smoking is a traditional method of tobacco smoking, especially in the Eastern Mediterranean region (EMR), and is now increasing in all over the world under different names (i.e. argila, argile, arghile, goza, hubble-bubble, hookah, hukah, madaáh, narghile, sheesha, shisha, water-pipe), but under all of those names the same method of smoking is used, in which the smoke passes through water before inhalation by the smokers (Maziak et al., 2004).
The tobacco used here in smoking is either a pure unflavoured tobacco in which case it is known as: Agamy or a fruit flavoured tobacco, which is usually prepared by adding honey, glycerin and other flavours with mild aromatic smoke, known as Maassel. (Rastam et al., 2004).
According to the size of the heads of the water-pipe, there are 2 kinds: large or small. The large one is nearly 20 g of tobacco, the small one contains around 10 g of tobacco.
Smoking 1 g of Agamy produces 35.65 mg; (range of 30.0–41.3 mg) of nicotine, but 1 g of Maassel produces 3.35 mg; (range of 1.8–6.3 mg) of nicotine (Hadidi and Mohamed, 2004).
This method of smoking contains small but not negligible amount of the addictive substance nicotine (Shafagoj and Mohammed, 2002, Shafagoj et al., 2002, Shihadeh, 2003).
A high percentage of some populations in the EMR smoke using a water-pipe. Nowadays water-pipe smoking is becoming a global phenomenon.
Relatively little research has been devoted to the health effects of water-pipe smoking, a few studies linked to cancer, respiratory and cardiovascular diseases (Gunaid et al., 1995, Bedwani et al., 1997, Kiter et al., 2000, Jabbour et al., 2003).
We used the non-invasive spectral method, which is based on continuous blood pressure recordings according to Peňáz (1973). We estimated BRS, which corresponds to the gain of the system with spontaneous systolic blood pressure fluctuations as input and cardiac interval fluctuations as the output and is expressed in ms/mm Hg (Robbe et al., 1987).
In our study, in normotensive subjects we studied the changes of BRS before and after water-pipe smoking, and the change patterns in heart rate and blood pressure.
Section snippets
Subjects
Twenty normotensive volunteers (20 men, of average age 27 ± 6 years (mean ± S.D.), in a range of 20 to 40 years) who served as their own control, (for characteristics see Table 1) were tested before water-pipe smoking, and after water-pipe smoking. All subjects gave their informed consent before the study. The protocol was approved by the Ethical Committee of the University.
Measurements
The subjects rested and adjusted to the laboratory's environment before monitoring. Meanwhile, a photoplethysmographic
Results
Table 2 presents the mean values ± S.D. of the tested parameters obtained before and after water-pipe smoking during controlled breathing rate 0.33 Hz. Smoking increased the SBP, DBP, MBP; and decreased IBI and BRS. The differences between mean values of IBI, DBP, MBP before and after water-pipe smoking were statistically significant (p < 0.001), as well as SBP and BRS (p < 0.01). PP and BRSf values before and after the water-pipe smoking, while not statistically significant, were slightly changed.
Discussion
The main findings of this study are that water-pipe smoking increases the heart rate, systolic, mean and diastolic blood pressure, and decreases the baroreflex sensitivity. Because this study is the first of this kind we can compare our results with cigarette smoking only.
Cigarette smoking increases the activity of the autonomic nervous system (the sympathetic part), increases heart rate and blood pressure and impairs the baroreflex (Niedermaier et al., 1993, Grassi et al., 1994, Piha, 1994,
Limitations
This study was based on a small group of healthy subjects and studied the acute effect only. Studies of the long-lasting effects, as well as epidemiological studies on larger populations are needed. Such studies would further confirm the risks of water-pipe smoking to public health.
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