Before taking a BP, how long should a patient abstain from caffeine?

• A. 30 minutes.
• B. 5 minutes.
• C. 15 minutes.
• D. 2 hours.

Answer: (A)

Caffeine can cause a temporary rise in blood pressure by stimulating the sympathetic nervous system and blocking adenosine receptors, which leads to vasoconstriction and a higher heart rate. To get an accurate blood pressure reading, it’s important to let these effects wear off before taking the measurement. Abstaining from caffeine for about 30 minutes before measuring is a practical, widely used guideline that helps minimize artificial elevations.

Five minutes is usually too soon, as the stimulant effects can still be present. Fifteen minutes may reduce some impact but isn’t reliably enough to ensure a baseline reading. Two hours is longer than necessary for most measurements and can be impractical in clinical or home settings.