Loving_Heart replied: "Caffeine is a mild stimulant found in coffee, tea, chocolate and many soft drinks. Too much caffeine can cause nervousness and jitters. It may also increase your blood pressure. The amount of caffeine in two to three cups of coffee can raise systolic pressure 3 to 14 millimeters of mercury (mm Hg) and diastolic pressure 4 to 13 mm Hg in people without high blood pressure. Among people who don't consume caffeine on a regular basis, caffeine can cause a temporary but sharp rise in blood pressure. Exactly what causes this spike in blood pressure is uncertain. Some researchers suggest that caffeine narrows blood vessels by blocking the effects of adenosine, a hormone that helps keep them widened. Caffeine may also stimulate the adrenal gland to release more cortisol and adrenaline, which cause your blood pressure to increase. Observational studies can be confusing. Some research has found that people who regularly drink caffeine have a higher average blood pressure than those who drink none. Other research has suggested that regular consumers of caffeine develop a tolerance to it — and as a result, caffeine doesn't have a long-term effect on their blood pressure. In another twist, a 12-year study of 155,000 women found that drinking caffeinated cola may be associated with an increased risk of high blood pressure. However, the same causal relationship was not found with caffeinated coffee. In fact, the study suggested that women who drink caffeinated coffee may actually have a reduced risk of high blood pressure. Similarly, a recent (2007) study claims that women who drink six cups of caffeinated coffee a day have lower risks of high blood pressure than do women who drink three or fewer cups daily. The same study found that men and women who never drink coffee also have lower risks of high blood pressure. As a precaution, some doctors recommend limiting caffeine to 200 milligrams a day — about the same amount as in two 12-ounce cups of brewed coffee. Keep in mind that the amount of caffeine in coffee and soft drinks varies by brand. Also, avoid caffeine right before activities that naturally increase your blood pressure, such as exercise, weightlifting or hard physical labor. To see if caffeine might be raising your blood pressure, check your blood pressure within 30 minutes of drinking a cup of coffee or another caffeinated beverage you regularly consume. If your blood pressure increases by five to 10 points, you may be sensitive to the blood-pressure-raising effects of caffeine. If you plan to reduce your intake of caffeine, do so gradually over several days to a week to avoid withdrawal headaches."

A.V.R. replied: "There is some doubt about caffeine's effect on blood pressure. There is some study showing that caffeine intake increases the risk for those already having hypertension. There is, however, some studies that show that it does not have any long term risks for normal people. Isolation of caffeine from coffee: Coffee has more caffeine than tea. 1. Make a strong infusion of coffee preferably in an espresso machine. Allow to cool. 2. Take the infusion into a stoppered glass flask (conical or spherical). Add an equal volume of Trichloroethylene (TCE) Caution: Both must be at room temperature Avoid breathing TCE vapors 3. Close the flask, shake the flask enough to mix the two liquids. Caution: Vigorous shaking can cause TCE to build up pressure inside. 4. Periodically, slowly open the stopper just enough to leak out any TCE vapor that buils up. Open the stopper away from your face or any body else's nearby. Do this for about 5 minutes. 5. Pour the mix into a separating funnel. After the layers separate drain and separate the infusion from the TCE layer. Store the TCE extract in a flask for later use. 6. Repeat steps 2 to 6 using a new lot of TCE and the infusion separated in Five. Collect the second extract of TCE into the same flask containing the first extract. Discard the infusion. 7. Assemble a distillation column and distill off the TCE. The residue in the flask is the caffeine that was in the original coffee. This will be crude. May require redissolving in TCE , filtering and recrystallization. This can be done in an evaporating dish in a fume cupboard. I am afraid that, while this part may prove of interest, the other one about its effect on hypertension may be a disappointment. This will constitute human experimentation and is subject to various regulations. As pointed out earlier it may well be a wild goose chase. Better do the first part to show that caffeine can be isolated. Rely on literature search for the second part. Here is a list of publications on that:"

MISS B.ITCH replied: "Blood pressure can easily be changed by diet & lifestyle change. My high BP started in pregnancy & continued for 3 years. I was taking meds for it & eventually my BP was too low so I slowly came off the meds. Being on these meds for such a long time has caused me to have a lot of shortage of breath problems, so it was good to come off them. You have to be weaned off them. You should never go cold turkey on these things. I have since tried to avoid stressful situations (not always easy as a parent), cut down on fast food & chocolate and my BP has been fine for well over a year. My Dad has high BP & his temper is as bad as mine so it may be a link there. He doesn't exercise much & I don't do any at all apart from a lot of walking. Good luck :-)"