Tachycardia and Anxiety

Hi everyone,

I've experienced some troubling instances of tachycardia lately (110 bpm-120 bpm that won't slow down even after several hours) and I'm wondering who else has issues with this. My heart rate at rest on waking up/while lying in bed is about 57-60bpm, which usually means you're fit. However, once I'm up and about it's usually tachycardic. It especially baffles me when it happens and I'm just hanging out with friends--lying in the park on a beach towel, hanging out at the local pub, or playing board games even.

A few years ago, I had an ECG, a chest x-ray and a Holter monitor test which all came back negative for any issues. I doubt much has changed in that time. I went to the health center on my college campus last week and had blood tests (a blood count, something to test for nutrient deficiencies, and a test for hyperthyroidism).

Is it wrong that I hope it's hyperthyroidism? That can cause racing heartbeat, insomnia (which I regularly experience), weight issues (I'm a "hard gainer"), anxiety and tremulousness. To say that my racing heartbeat and anxiety are caused by a physical problem gives me more hope because physical problems seem more treatable than mental ones. I've been treated for anxiety time and again but can't shake it.

I've also heard there's something called postural tachycardia where you're body can't tolerate orthostatic pressure and so your heart rate elevates to compensate. That sounds scarier to me than hyperthyroidism and I think it's rarer/they know less about it, so I'm sort of hoping it's not that, but it certainly wold explain it.

I think exercise would be good for me but I'm afraid to exercise because my heart races at rest--I don't want to put it through too much while exerting myself. And so many symptoms of exercise mimic a panic attack that it usually sends me into one. Ugh.