This is a cultural difference that many immigrants to Germany notice. Germans regard many ailments as related to the circulatory system.

As a Brit I would probably say I feel groggy / out of sorts / faint/ rough / weak, but wouldn't think of my blood pressure being up or down.

Here are some extracts from fellow immigrants to sustantiate my claim.

"Another metaphor for illness you will become familiar with is that of 'Kreislaufbeschwerden'. Circulatory complaints, however, are rather totally unknown in the English speaking world as an intelligible description of ailments. In Germany this metaphor enjoys greatest *ahem* currency. What exactly the 'Kreislauf' is seems secondary to the concern to articulate discomfort"

http://www.cinestatic.com/infinitethought/200...

"In Germany, a lot of ailments seem to focus on the Kreislauf - the circulation system. If you're feeling poorly, you're probably having a Kreislaufkollaps - a collapse of your circulatory system, and your doctor will be able to fix you up with any number of pills and potions to remedy this condition."

http://justcallmemausi.blogspot.com/2005/06/i...

or more ironically:

"the second most popular German pastime, having troubles with your blood circulation, in German: Kreislaufstörung . Anyone planning a trip to Germany : better learn this expression by heart and use it a soften as possible. This can be useful: A normal citizen of the world admits, after being horribly drunk at night and after not having enough sleep, that he or she has a hangover. In Germany , one can avoid this guilty plea: That is not a hangover, that is just a Kreislaufstörung . You are not to blame for it, it can happen to anyone. Smoking a pack of cigarettes and feeling sick? Kreislaufstörung . Caught drunk driving? Kreislaufstörung . Falling asleep in a meeting? Kreislaustörung".

http://www.germanfortravellers.com/culture/et...