Can drinking coffee raise blood pressure?
The Indian Express | 21 hours ago | 28-03-2023 | 11:45 am
The Indian Express
21 hours ago | 28-03-2023 | 11:45 am
You may have often been alerted about the stimulant properties of coffee (or equivalent sources of caffeine) in elevating your blood pressure (BP) levels but so far, no clinical study has been able to prove that coffee-drinking is bad for hypertension. Of course, as with all foods and beverages, doctors advise coffee consumption in moderation simply because it does spike blood pressure temporarily before settling down and is, therefore, considered a stressor for those already hypertensive.Explains Dr Balbir Singh, Chairman, Cardiac Sciences, Cardiology, Cardiac, Electrophysiology-Pacemaker, Max Hospitals, “The BP spike is very temporary and then goes down, so one cannot say that coffee-drinking has a significant long-term effect on BP. This is the reason why we advise people to measure their BP for trustworthy readings 30 to 45 minutes after they have had their cup of coffee. It is for the same reason that we advise people not to have coffee before they undertake any intense physical exercise or strenuous activity which can raise your BP. Even then the BP response varies from person to person. Some studies have shown that in habitual coffee drinkers, the spiral effect reduces over time as they develop tolerance to the brew, compared to non-regular drinkers. Why this happens is yet to be pin-pointed. Some researchers believe that caffeine blocks a hormone that widens our arteries. Others attribute the BP spike to coffee spurring the release of extra adrenaline. At the same time, latest research on caffeine, particularly over the last year or so, has focussed on the encouraging effects of antioxidants and flavonoids present in coffee in reducing overall inflammatory markers in the body.”What worries Dr Singh is that all available research on coffee in the West is done with the way the brew is had there, which is black. “So even if research finds no convincing correlation between drinking coffee and hypertension, it would not apply to the coffee-drinking culture in India. We have our coffee with a lot of milk and sugar and that’s harmful for the body at many levels. Latest research says sweeteners too raise the risk of blood clotting, which is worrisome for heart health. But one to two cups of black coffee are not as worrisome. I have black coffee myself,” says he.Given that coffee is a stimulant, a cup increases your BP by five to ten points for a short period of time. Says Dr Udgeath Dhir, Director and Head of Cardiothoracic and Vascular Surgery (CTVS), Fortis Memorial Research Institute, “This is a rise similar to when we exercise. In a two-year study of 45,589 men, between the ages of 40 and 75, which was released last year, researchers of the Harvard Medical School found no link between coffee consumption and the risk of coronary artery disease even in heavy drinkers. While regular coffee was found to be safe, they found a decaf version to be associated with a slightly increased risk of heart disease, though it claimed the link was weak. Studies have found that coffee does not seem to disrupt the heart’s rhythm, even in recent heart attack patients.”The Harvard Medical School last year even published the findings of a study by US and Swiss scientists on 15 volunteers, who didn’t have a high blood pressure and six of whom were just habitual coffee drinkers. According to the study, “The researchers monitored each volunteer’s blood pressure, heart rate and sympathetic nervous system under four conditions: before and after drinking a triple espresso, before and after drinking a decaffeinated triple espresso, before and after receiving 250 mg of caffeine by intravenous injection, and before and after an intravenous placebo (salt solution). A triple espresso caused quite a jolt, and it did jolt blood pressure readings. But although blood caffeine levels rose to a similar degree in all the subjects, not all experienced a rise in blood pressure. In fact, espresso did not boost the pressures of habitual coffee drinkers, though it raised systolic pressure readings on average by 13 mm Hg and diastolic pressures by 7 mm Hg in subjects who were not coffee drinkers. Espresso is strong stuff, but an intravenous slug of caffeine should be even more potent. Indeed, blood caffeine levels rose to the same degree after the caffeine injections and the espresso. But the straight-up caffeine had a much smaller effect on blood pressure than the espresso, boosting systolic blood pressure by an average of just 6 mm Hg. Moreover, the coffee drinkers and the non-drinkers responded similarly to intravenous caffeine.” A review of 34 studies showed that two cups resulted in an average increase of 8 mm Hg and 6 mm Hg in systolic and diastolic blood pressure, respectively.Dr Dhir’s advisory is avoiding coffee before sleep as it could interfere with the restorative process of cell repair. “Coffee is a sleep disruptor. The US Food and Drug Administration (FDA) says 400 milligrams a day of caffeine is generally safe for most people. However, if you are already hypertensive and worry about its spiking effects, no matter how temporary, limit yourself to two cups a day,” he says.Far more important is the way we control blood pressure through moderate physical activity for anything between 30 and 45 minutes five times a week. “A cup or two of coffee won’t harm us but ignoring high blood pressure levels or avoiding lifestyle correction means that the resultant condition could impact your vascular system, damage arteries, affect the aorta and end organs,” warns Dr Dhir.
