Timing of blood pressure measurements related to caffeine…

A meta-analysis published in the Annals of Pharmacotherapy suggests that asking patients to abstain from consuming caffeine within 30 minutes of having a blood pressure measurement is insufficient. The author based this assumption of the pharmacokinetics of caffeine with it peaking 30-120 minutes after consumption and a half-life of 3-6 hours, allowing the effects of caffeine to extend past the standard wait time of 30 minutes. The magnitude of blood pressure changes associated with caffeine use depend on the hypertensive status of the patient, age (greater elevations ar seen with advanced age and in younger patients), physical and psychological stress, past caffeine use and tolerance, a process that occurs due to chronic caffeine consumption that may diminish the body’s response to caffeine. Caffeine was shown to acutely change systolic blood pressure by 3-15 mmHg and diastolic blood pressure by 4-13 mmHg. The study concluded that rather than having patients refrain from consuming caffeine 30 minutes prior to blood pressure monitoring, the alternative approach should be to simply ask patients about daily and recent caffeine intake. This will assist in appropriately interpreting blood pressure values, and as always, provide patient counseling and education on the effects of caffeine on blood pressure and general health.

How much caffeine is too much?

A day without a cup of coffee or a cola is unheard of for most people. In fact, 9 in 10 Americans consume some type of caffeine regularly. The effects of caffeine can easily be felt in less than an hour. You are more alert, you feel more productive, and your mood is instantly lifted. But the effects of caffeine are often not long lived, leaving you thirsty for more. For most people, 200-300mg (2-3 cups of coffee) are not harmful, but for some who are caffeine sensitive (people with low BMIs, or those under stress), those 23 cups could cause exaggerated effects of anxiety, restlessness and irritability. About 500-600 mg of caffeine daily, or 4-7 cups of coffee a day, is considered an excessive amount of use. Consumption of this much of caffeine could lead to muscle tremors, sleeplessness, headaches, abnormal heart rate and even gastrointestinal problems such as nausea and diarrhea. Abrupt decreases in caffeine can lead to withdrawal, so it is best to decrease the consumption gradually. When trying to curb your caffeine habits, gradually reduce the amount by drinking one less cup of coffee or bottle of soft drink. You may also replace caffeinated drinks with decaffeinated beverages or teas.