However, when you want to compare a Boolean variable with the literal Boolean value true or false, it is not necessary to do an explicit comparison, because the result of evaluating a Boolean value is that Boolean value. For example, the expressions
The nicotine in cigarette smoke is a big part of the problem. It raises your blood pressure and heart rate, narrows your arteries and hardens their walls, and makes your blood more likely to clot. It stresses your heart and sets you up for a heart attack or stroke. Know Your Blood Pressure Numbers.
The action of nicotine in the body is very complicated. It is a mild stimulant which has an effect upon the heart and brain. It stimulates the central nervous system causing irregular heartbeat and blood pressure, induces vomiting and diarrhea, and first stimulates, then inhibits glandular secretions.icotine seems to provide both a stimulant and a depressant effect, and it is likely that the effect it has at any time is determined by the mood of the user, the environment and the circumstances of use.