How does caffeine intake affect immediate BP measurement?

• A. Caffeine has no effect on BP.
• B. Caffeine permanently raises BP.
• C. Caffeine reduces BP.
• D. Caffeine can transiently raise BP; avoid caffeine-containing products for at least 30 minutes before measurement.

Answer: (D)

Caffeine acts as a stimulant that can cause a temporary rise in blood pressure because it increases sympathetic nervous system activity and can cause vasoconstriction. This effect happens fairly soon after ingestion and is short-lived, not a permanent change. Because the goal of measuring BP is to assess resting pressure, recent caffeine can bias the reading upward. To avoid this, it’s recommended to avoid caffeine-containing products for about 30 minutes before taking a BP measurement. This explains why the correct choice says caffeine can transiently raise BP and to limit intake before measurement. The ideas that caffeine has no effect, permanently raises BP, or reduces BP don’t align with the acute, reversible impact caffeine can have on BP.