Acute effects of coffee on skin blood flow and microvascular function

- After drinking a single cup of coffee, endothelium-dependent vasodilatation in the skin is acutely enhanced.
- After drinking a single cup of coffee, blood flow in the fingertip is substantially reduced.
- Intake of caffeine through drinking caffeinated coffee acutely augments microvascular reactivity.

ObjectiveStudies on the acute effects of coffee on the microcirculation have shown contradicting results. This study aimed to investigate if intake of caffeine-containing coffee changes blood flow and microvascular reactivity in the skin.MethodsWe measured acute changes in cutaneous vascular conductance (CVC) in the forearm and the tip of the finger, the microvascular response to transdermal iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) and post-occlusive reactive hyperemia (PORH) in the skin, after intake of caffeinated or decaffeinated coffee.ResultsVasodilatation during iontophoresis of ACh was significantly stronger after intake of caffeinated coffee compared to after intake of decaffeinated coffee (1.26 ± 0.20 PU/mm Hg vs. 1.13 ± 0.38 PU/mm Hg, P < 0.001). Forearm CVC before and after PORH were not affected by caffeinated and decaffeinated coffee. After intake of caffeinated coffee, a more pronounced decrease in CVC in the fingertip was observed compared to after intake of decaffeinated coffee (− 1.36 PU/mm Hg vs. − 0.52 PU/mm Hg, P = 0.002).ConclusionsCaffeine, as ingested by drinking caffeinated coffee acutely improves endothelium-dependent microvascular responses in the forearm skin, while endothelium-independent responses to PORH and SNP iontophoresis are not affected. Blood flow in the fingertip decreases markedly during the first hour after drinking caffeinated coffee compared to decaffeinated coffee.