I'd imagine a little bit of caffeine a day is not much of a problem for most of us. Recall this recent article on Dr. Biffa's sight about coffee high in caffeine and it effects on blood pressure and heart disease.
"Coffee safe for those with history of raised blood pressure"
"These studies showed that, overall, higher intakes of coffee were not associated with increased risk of cardiovascular disease.
In short, coffee seems like a generally safe option for people with a history of raised blood pressure.
One of the points the authors of this paper make is that while caffeine can have adverse effects on markers for disease (such as blood pressure), other elements in coffee can have beneficial effects. For example the compounds chlorogenic acid and trigonelline and the mineral magnesium improve glucose metabolism, reduce inflammation and enhance the healthy functioning of the inside of the blood vessels.
While I?m a fan of coffee, I do recommend some caution. Too much caffeine, in addition to effects on the cardiovascular system, can do other things too such as disrupt sleep, which can have implications for health and wellbeing. Some people metabolise caffeine (in the liver) very quickly and throw back a double espresso after dinner and still sleep like babies. Others, though, are not so fortunate, and can be tripped up by caffeine consumed hours before. If you think you?re caffeine-sensitive, then I?d advise keeping coffee intake generally low and confining it to the morning only."