Quick background: I'm a 26 year old male, generally in good shape. 6'2, 200 lbs and normally work out 5-6 days a week.
Around January 8th, I completed a challenge called the Tough Mudder. It was a 12.5 mile long obstacle course. I had never done anything like it before. This competition completely exhausted me. The day after I woke up feeling different. Kinda lightheaded, but more of just not myself than anything else. Anyway, I took about 4 days off from any physical activity, and ever since then, I've still been feeling lightheaded most days, and any physical activity exhausts me immediately and my heart instantly races like it hasn't done before.
Some examples would be:
-Playing in a fastpitch softball tournament, I caught one inning and almost passed out. Had one at bat where I took every pitch, but nevertheless my heart was practically beating out of my chest.
-Mopping around the house.
-Taking out the cat litter.
-Attempting to swim laps and burning out from a lap and a half.
-Opening the lid off of a jar, even to the point where I can feel my heart working harder.
Basically, any physical activity has been impossible. I ended up in the hospital at the softball tournament cuz my teammates suggested it. I had tons of tests done including bloodwork, EKGs, Echo, CTscan, MRI. Everything came back fine. The problem is that I was resting the entire time. Sometimes I still feel a little lightheaded, but unless I'm doing physical activity I feel ok.
Both cardiologists I've seen thought that everything seems fine and that I completely burnt myself out from the Tough Mudder. Before the race and after, I've always been good with fluid intake, including electrolytes, so there's no way I could still be dehydrated.
I'm still awaiting them to contact me for my stress test and heart monitor, but it's been over a month and it's still the same.
Not only does my heart race, but I feel like it kinda hurts when I strain myself in anyway, like lifting a box.
Any help would be appreciated.