Coffee and Blood Pressure: Does It Raise or Lower Blood Pressure

Caffeine is found in coffee, tea, and other beverages, and the question of its link to blood pressure arises for many who see unusual numbers on a blood pressure monitor. Below is the mechanism: where caffeine actually shifts readings, and where the reaction depends on the state of the blood vessels and on habit of drinking the beverage.

Does coffee raise or lower blood pressure: what observations show

The short answer: under the influence of caffeine, blood pressure rises; with normal blood pressure, no significant changes are observed. Caffeine intensifies cardiac activity and speeds up the pulse. Mood under the influence of caffeine may improve, but after 3–6 hours the effect of caffeine passes, giving way to fatigue and reduced performance.

The second factor is the baseline readings. In collapse and shock states, blood pressure rises under the influence of caffeine: simultaneously with excitation of the vasomotor center and increased cardiac work, the vessels of skeletal muscles, brain, heart, and kidneys dilate.

Why caffeine can raise blood pressure

The mechanism is conveniently pictured as a pump and pipes: the heart is the pump, the vessels are the pipes, and pressure is the force with which blood presses on their walls. Caffeine blocks the enzyme phosphodiesterase, which breaks down cAMP, and the mediator accumulates in cells; the result is adrenaline-like effects. Myocardial contractions become more intense and more frequent, and the vasomotor center is excited.

The second pathway is brain adenosine receptors: adenosine reduces excitation, and caffeine, similar to it in structure, takes its place. The lumen of vessels changes in different directions — cerebral arteries constrict, while the vessels of skeletal muscles, heart, and kidneys dilate. The number on the blood pressure monitor is the sum of these influences.

Caffeine in other beverages

The active substance is the same — caffeine — and it is not only in coffee: beverages with a high caffeine content also include tea and cola; it is found in mate, cocoa, energy drinks, and in some pharmacy medications.

Coffee with high blood pressure and hypertension: what to watch

With elevated blood pressure, excess caffeine is considered one of the lifestyle factors that are taken into account. Blood pressure does not produce symptoms for a long time, so blood pressure is judged by measurements, not by how one feels. The threshold for elevated blood pressure is 140/90 and above at the doctor's office, 135/85 and above with home measurement. A more detailed grading:

• normal — below 120 and below 80;
• elevated — 120–129 and below 80;
• stage 1 hypertension — 130–139 or 80–89;
• stage 2 hypertension — 140 and above or 90 and above;
• hypertensive crisis — above 180 and above 120.

Persistently high blood pressure over time forces the heart to work under overload and increases the risk of heart attack, stroke, heart failure, and kidney disease.

Coffee with low blood pressure: why the reaction varies

With low blood pressure, coffee is perceived as a way to perk up, and this partly matches the mechanism: caffeine constricts cerebral arteries, speeds up the pulse, and excites the vascular center.

Another reason for the variation is habit. With long-term use, more adenosine receptors form in brain cells, and the effect of caffeine gradually decreases. With sudden withdrawal, adenosine occupies all available receptors: fatigue, drowsiness, and low mood appear.

When to see a doctor

A reason to check blood pressure at a pharmacy or with a doctor is suspected high blood pressure or risk factors. Those aged 40 and older who have not measured their blood pressure for more than five years are advised to check it. High blood pressure usually has no symptoms; rarely there may be headaches, blurred vision, or chest pain. The diagnosis is confirmed by several measurements on different days, including home measurements and 24-hour monitoring.

A cup of coffee by itself is not a reason to call an ambulance. Calling 103 or 112 is necessary for sudden pain or discomfort in the chest that does not pass — squeezing, burning, a feeling of heartburn; for pain radiating to the arm, neck, jaw, abdomen, or back; for sweating, nausea, dizziness, or shortness of breath together with chest pain. A separate reason is blood pressure above 180/120.

This material is for reference: it explains the mechanism and does not replace a doctor's consultation — blood pressure monitor readings and complaints are discussed with a doctor, not with a cup of coffee.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer