Look up paroxysmol supraventricular tachycardia (PSVT) - a not uncommon heart arrhythmia . I was a runner, did ballet etc and one day while calmly at a cosmetic counter feeling happy looking at lipstick i felt my heart start racing - mine went up to 180 and higher. It would happen like you turned a light switch on and then, off, after 20 minutes.I was young and healthy and I was treated horribly by doctors who treated me as if i wereneurotic , having panic attacks, exaggerating, wanting attentio etc. It took me TWENTY YEARS to get diagnosed. During that time, I did my own research and tried maneuvers to break the tachycardia (whch means a heart rate over 100 pbm) I found in Merck manual and elsewhere .. this was long before we had the internet. Carotid artery massage,pressure on eyes, bearing down - did not work. I finally found for me the mammalian diving reflex ( plunging face in cold water and breathing slowly ) worked like a charm. Due to my work (and my work changed course because of my interest in medicine ) I ended up being respected and not treated like a neurotic person somehow making up my acute episodes - I was in the office of the chairman of the department of medicine, a cardiologist at a large university and health center, due to my work and i finally just let it out - what i had been going through with my heart. In TWO MINUTES he said " you aren't having panic attacks - it's WPW or PSVT . And we can fix it!" I collapsed sobbing. I had given up having someone actually LISTEN TO ME. those were my own "diagnoses" and i was right!! I had worn monitors but never were they kept on me long enough to catch the arrhythmia. Finally this wonderful doctor kept a monitor on me for weeks to document the arrhythmia so insurance would approve an electrophysiology study (EP study); first tried beta blockers but made me feel exhausted and rotten. I had an EP study during which my heart went up to 220 ! an ablation was performed - I went home less than two hours afterwards to cook dinner for my son and only had a few skips here and there over the next 12 years or so. The last 3 years , I've had one recurrence a year oddly . I have a loop recorder now (technology has so improved ) but no more occurrences so far. Sometimes psvt can come back after an ablation - or it may recur so rarely it's no big deal. I hope that's the case now for me. I cannot diagnose you but I can say that it wouldn't hurt to ask your doctor about PSVT.