There is good evidence that even passive smoking (non-smokers who happen to inhale tobacco smoke) are at increased risk for heart attacks. Its common experience for doctors to note sudden deaths due to heart attacks linked temporally with smoking before going to the toilet in the morning. Your BP measurement is just one measure of the disease called hypertension. Controlling it doesnt remove all its bad effects i.e. even after BP is controlled heart attacks and strokes are more common in hypertensives than in people who do not have hypertension.