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.
Periods of anxiety trigger the release of hormones that cause increased heart rate and decreased blood vessel diameter, both of which lead to increased blood pressure. 1  The effect of stress on short term blood pressure can be dramatic, leading to mean arterial pressure increases of 30%-40%. These changes are short lived, though, with heart rate, blood vessel diameter, and blood pressure returning to normal as the hormones are eliminated.