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.
Nicotine can cause many health problems. It can temporarily raise blood pressure and heart rate because it causes blood vessels to narrow. Nicotine can also make the blood more likely to clot and block an artery, and it can cause damage to the lungs and make breathing difficult. Nicotine in the body is first processed by the liver and then excreted by the kidneys. Over time nicotine can have negative effects on the kidneys.