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 Nicotine, although very similar to Acetylcholine, does not act exactly like the neurotransmitter and consequently causes the systems that it affects to function abnormally. The Nicotine causes a spontaneous release within the brain of other neurotransmitters that affect mood, appetite and memory. Additionally, many systems such as the respiratory and cardiovascular systems are sped up (4). Nicotine causes the pancreas to release glucose, causing smokers to be marginally hyperglycemic.