Why heart beats fast? - #12308
I am feeling a bit worried because my heart has been racing like crazy, and I'm trying to understand why heart beats fast, like, what could be causing it? It's started over a week ago when I felt this huge rush of anxiety before a big presentation at work. Really thought it was just nerves, but now it happens even when I'm sitting at home, just watching TV! Sometimes I'll be totally calm and, outta nowhere, my heart starts pounding like I just ran a marathon. Usually, I’m pretty healthy, maybe a little stressed but nothing wild. I did go to the doc and got some tests done, all came back normal. They said it's probably anxiety but I can't shake off that feeling, y'know? Why heart beats fast sometimes and then it's fine other times? Could it be something else, like diet or caffeine? Sometimes I drink a lot of coffee, especially at work, so could that be it? I'm worried it could lead to something more serious. Has anyone else felt this way? Why heart beats fast in those moments? Any advice or experiences would be super helpful!
100% Anonymously
No sign-up needed.

Doctors’ responses
Your symptoms of a fast heart rate, especially following a stressful event like a work presentation, can certainly be linked to anxiety, which can trigger your heart into what’s called a “fight-or-flight” response. However, since it’s recurring even at rest, it’s crucial to consider other possible contributing factors. You’ve mentioned caffeine intake—coffee is a well-known stimulant that can cause your heart rate to increase, particularly if consumed in larger amounts or if you’re especially sensitive to it.
Beyond anxiety and caffeine, there are several other reasons why your heart rate might speed up. Things such as dehydration, lack of sleep, or even hormonal changes, like those related to thyroid function, can play a role. Stress doesn’t just have to be mental; physical strain from illness or even subtle conditions like anemia can stealthly elevate heart rate. It’s reassuring that your tests were normal, yet it’s also important to keep a close eye on your overall lifestyle—ensure you’re getting adequate rest, staying hydrated, and perhaps considering cutting back on coffee to see how your body responds.
Sometimes, lifestyle adjustments are enough to resolve the issue, but it’s vital to remain vigilant. If the palpitations persist or are accompanied by other symptoms like dizziness, chest pain, or shortness of breath, these are red-flag signs warranting further medical evaluation—they could indicate arrhythmias or other cardiovascular conditions needing attention. When avoiding caffeine, incorporate relaxation practices like yoga or deep breathing exercises to manage stress proactively. It’s understandable to feel concerned, but considering these strategies and monitoring your symptoms closely can offer a practical path forward. If symptoms persist, a revisit to your GP or a cardiologist for potential additional testing, including a Holter monitor or stress testing, might be the next step to ensure nothing more sinister is at play.
100% Anonymously
Get expert answers anytime, completely confidential. No sign-up needed.
About our doctors
Only qualified doctors who have confirmed the availability of medical education and other certificates of medical practice consult on our service. You can check the qualification confirmation in the doctor's profile.