Nicotine in cigarettes ( and pinch tobacco , patches , gums , etc .)stimulates the production of dopamine in the brain . Dopamine is a 'feel good' chemical . It can make you play longer and even get over the bad tate of losing quicker . in an average casino , after 4 hours , Non-smokers have about 70% ( on average ) of the metabolized Nicotine in their blood as the chain smokers do . Casinos experiment with injecting various things such as oxygen and scents into the casino air supply in order to make the gamblers feel better . But they cannot legally put nicotine into the air supply . Therefore they depend of the 20% to 30% of the casino population who are smokers , to put it there for themselves AND the other 70% to 80% of the casino population . They don't want to encourge patrons to use patches etc. ( after all they could give out free nicotine gum or mints to people ) because this affects a drug for that encouraging the entire casino population to play ( on avg. lose ) more . I just read that from 1997 to 2005 the tobacco industry has raised the amount of nicotine ( the addictive chemical in cigs ) by 11% . Therefore the second hand smoke contains more . Maybe even more than the 11% increase since the inhaled smoke is cooler and filtered .