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Myth check

Does coffee raise blood pressure? The hour after, and the years after

With high blood pressure, a 200 to 300 mg caffeine dose raised it for three hours or more in tests. Over years, coffee drinkers were no more likely than others to develop high blood pressure.

Caffeine

Many people assume their coffee keeps their blood pressure up. In people who already have it high, 200 to 300 mg of caffeine raised it within an hour and kept it up for three hours or more, in short test sessions. Over years, across 13 studies, coffee drinkers went on to develop high blood pressure no more often than others, though they chose their own habits and some may have cut back. The rise after a dose is real; the habit itself was not linked to developing the condition.

The findings behind this

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Physical & bodyWith high blood pressure, caffeine spikes it; 2 weeks of coffee didn't

In people with high blood pressure, 200 to 300 mg of caffeine raised it for three hours or more. Over about 2 weeks, coffee raised it no more than going without caffeine.

★★★Well replicated — this finding’s sources average out to meta-analyses, systematic reviews or high-powered trials.The hour-by-hour rise comes from single doses given in short test sessions, which may not match a regular drinker's morning cup. Only three trials, of about 2 weeks each, looked past the first day, too short to catch a change that builds more slowly. An older review found the rise strongest in people who already have high blood pressure, so it may be smaller in others.Click to keep this openSupport heart and blood flowCaffeine
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Physical & bodyYour coffee habit is not linked to higher odds of high blood pressure

Across 13 studies of 314,827 adults followed for years, coffee drinkers got high blood pressure no more often than others. A 10-year study using 24-hour readings agreed.

★★★Well replicated — this finding’s sources average out to meta-analyses, systematic reviews or high-powered trials.Coffee habits were self-reported and chosen, not assigned. People worried about their blood pressure may cut back, which would hide a rise among heavier drinkers. An earlier pooling of six studies found 9% higher risk at 1 to 3 cups a day and no rise above 3. American studies found slightly lower risk and European ones did not, so the overall figure averages a real split.Click to keep this openSupport heart and blood flowCaffeine

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