Does caffeine or coffee raise blood pressure?

Does caffeine raise blood pressure?

Yes, for a while. Trials gave 200 to 300 mg of caffeine to people with high blood pressure. It raised the top number by about 8 points and the bottom by about 6.

That’s roughly 2 mugs of coffee. A mug holds about 100 to 140 mg, though it varies a lot.

Think of a wave on the tide. It lifts the water for a while, but it doesn’t tell you where the tide is.

So a coffee just before a check can push one reading up. Blood Pressure UK says a one-off high reading is usually nothing to worry about.

Rest for five minutes and take it again. If it’s still high, check again another day. If it stays high for two or three weeks, see your doctor or nurse.

Does coffee cause high blood pressure?

Not in most big studies. Across 10 studies of 243,869 people, each extra daily cup went with a 2% lower risk of high blood pressure.

Another review found 1 or 2 cups a day weren’t linked to higher risk than none. A third found no clear effect either way, but called its evidence low quality.

These are links, not proof.

Pure caffeine may be a different story. In trials lasting a week or more, daily caffeine on its own raised the top number by about 4 points. Coffee raised it by about 1.

So these studies don’t show that cutting out coffee protects your blood pressure. For the wider picture, see is coffee good for you.

Can I drink coffee with high blood pressure?

Usually, in moderation. The NHS says don’t drink too much caffeine if your blood pressure is high. NICE tells doctors to discourage excessive coffee and other caffeine-rich products.

That last row is the group that differs. A Japanese study followed 18,609 adults aged 40 to 79 for about 19 years.

Some had readings of 160/100 or more. If they drank 2 or more cups a day, they were about twice as likely to die from heart disease or stroke. That’s compared with people with the same readings who drank no coffee.

It’s one study and a link, not proof. Green tea showed no such link. If your readings are this high, ask your GP how much coffee suits you.

How much caffeine is too much?

For most adults, up to 400 mg a day is unlikely to cause problems, says the Food Standards Agency (FSA). If you’re pregnant, the NHS advises no more than 200 mg a day.

But the FSA says people with high blood pressure or heart disease may feel effects at lower doses. So may people sensitive to caffeine.

Count every source. A mug of tea has about 75 mg. Some supplements contain caffeine too.

To tot up your drinks, see how much caffeine is in coffee.

Does coffee affect a blood pressure reading?

It can. Blood Pressure UK says don’t measure within half an hour of caffeinated drinks such as coffee. They can raise your reading for a while.

For the full method, see how to check your blood pressure at home. Higher at the surgery than at home? Read about white coat hypertension.

When to speak to a GP

High blood pressure usually has no symptoms. Get it checked at a pharmacy or GP surgery if:

• You think you might have high blood pressure, or might be at risk of it.
• You’re 40 or over and haven’t had it checked for more than 5 years.
• Your reading is 140/90 or higher at a clinic, or 135/85 or higher at home. The NHS usually counts this as high blood pressure.

Call 111 if you often have headaches or blurred vision, or chest pain that comes and goes. Also call if you have other symptoms you’re worried could be caused by high blood pressure.

Call 999 if you get sudden pain or discomfort in your chest that doesn’t go away. It can feel like squeezing, pressure, burning or indigestion.

Also call 999 if you get pain spreading to your arm, neck, jaw, stomach or back. The same goes if chest pain comes with sweating, feeling sick, light-headed or short of breath.

See also what is normal blood pressure.