Tobacco smoking is the act of burning the dried or cured leaves of the tobacco plant and inhaling the smoke for pleasure, for ritualistic or social purposes, self-medication, or simply to satisfy physical dependence or addiction. The practice was common among Native Americans throughout North and South America, and was later introduced to the rest of the world, via trade, following European exploration of the Americas.
Tobacco smoke contains nicotine, an addictive stimulant. The effect of nicotine in first time or irregular users is an increase in alertness and memory, and mild euphoria. In chronic users, nicotine simply relieves the symptoms of nicotine withdrawal: confusion, restlessness, anxiety, insomnia, and dysphoria. Withdrawal symptoms in chronic users begin to appear approximately 30 minutes after every dosecitation needed]. Nicotine also disturbs metabolism and suppresses appetite. This is because nicotine, like many stimulants, increases blood sugar.
It has been determined that all forms of tobacco smoking including cigarettes, cigars, pipes, bidis, hookahs, and other forms of tobacco use such as chewing tobacco and snuff are addictive. In fact, some news organizations compare the addiction potential of tobacco with that of heroin.
Medical research has determined that chronic tobacco smoking is a major contributing factor towards many health problems, particularly lung cancer, emphysema, and cardiovascular disease. Many countries regulate or restrict tobacco sales and advertising and require warnings to be placed prominently on the product packaging. Many governments now restrict or ban smoking in a variety of public venues over concerns of second-hand smoke, and possibly also to discourage tobacco use in general.