Brian Byrne, a tour manager in Los Angeles, was sipping an iced coffee a few years ago when he started feeling clammy. Soon, his symptoms worsened: shallow breathing, a hollow feeling in his chest and a rapid, thumping heartbeat. He went outside to get air. “At that point, I was having racing thoughts, feeling like I was having a heart attack,” he said.
When you’re working out or on a ride, those sensations aren’t a surprise. But the incongruity of sitting quietly at your desk while your heart is pounding, the way it might if you’ve just had some caffeine, can make some people experience that arousal as anxiety, says Joseph Trunzo, a deputy director of the School of Health and Behavioural Sciences at Bryant University in Rhode Island. On top of that, if you subconsciously label these symptoms as anxiety, you might reinforce the effect.
Caffeine affects everyone differently. If even a small amount of caffeine makes you anxious, you might have a certain genetic variant that influences how you metabolise caffeine, says Lina Begdache, a dietitian and associate professor of health and wellness studies at the State University of New York at Binghamton. In this case, you will process the caffeine more slowly, so it stays in the system longer and accumulates, potentially causing a more pronounced effect.
A few years ago, Ambardar had a patient who was dealing with severe anxiety. He had a high-pressure job and was drinking caffeine around the clock. Over several weeks, he reduced his intake and felt much more at ease. “He was really surprised and said, if he had known that this was the cause, he would have cut it back much sooner,” she recalls.