Here's How Caffeine Messes With Your Heart

It doesn't take a scientist to know that a cup of coffee can make you a little "jittery," or cause your heart to beat a little faster. But how does caffeine really affect your heart?
In a video from BBC 2's Trust Me I'm A Doctor program, researchers attempt to find out what exactly caffeine does to your heart with an experiment monitoring a person's heart rate with an MRI as they drank caffeine, in real time.
The volunteer, Evonne, abstained from caffeine for several days in preparation for the experiment, during which she drank an energy drink as researchers monitored her heart rate in the scanner.
Perhaps unsurprisingly, her heart began to beat faster as she consumed the energy drink. Just a few minutes later, her heart rate rose from 62 beats per minute to the mid 70s. That heart rate is about normal for a healthy person person at rest, according to University of Glasgow cardiologist Professor Colin Berry, who helped conduct the experiment.
But it wasn't just the pace in her heart rate that increased — the intensity of the beats also became stronger.
The question, however, is whether these effects are really bad for us, or if they're a harmless way of boosting our energy levels.
"It's entirely plausible that a drink that contains a lot of caffeine could have an unpredictable and enhanced effect on individual persons," Professor Berry said in the video.
For some people, caffeine can have serious effects. Two weeks ago, 16-year-old Davis Allen Cripe died after a combination of drinking a soda, a coffee, and an energy drink in a short amount of time, and suffering from a fatal change in heart rhythm. Though caffeine-related deaths are extremely rare, knowing the amount of caffeine that works for you is still important.
BBC's takeaway? If the caffeine you're consuming is giving you heart palpitations, you may want to dial it back.
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