Massive and sudden increase in heart rate and vomiting after when cycling The heart thing has happened a few times before, and the vomiting only once; but I haven't cycled in about a year and am getting back into it. I used to be a gymnast and did pretty extreme conditioning and never experienced this then; it's only with cycling.

My body doesn't feel fatigued, overall when this happens my muscles, legs etc feel like they could sprint for a mile with no issue. I'm never panting or struggling for breath or anything like that. It's just my heart and a sudden overwhelming sickness.

If you've seen Gattaca; the scene where the main character is on the treadmill with the fake heart monitor and then later collapses in the lockerroom is exactly how I would describe these episodes. In fact watching that scene makes me feel very uneasy and my hands start shaking; because the episodes feel like I'm about to die...it's extremely frightening.

Is this just a matter of endurance? I'm definitely going to talk to my physician next time I go for a check up. I don't eat large meals and I wait at least two hours before I go on a ride, and I don't particularly "go hard", I just kind of cruise. But I live in Seattle and it's pretty hilly here. Normally I just rest, lay down, sit-up, vomit, and I'm good to go. But I would really, REALLY prefer to not experience this ever again.

Advice?
Go to a doctor - this sounds dangerous. Anything you see on SE is not a substitute for professional medical advice and it sounds like you really need to see one.