I had a hole in my heart as a child that closed i'm now 18 and suffer heart palpations and my heart rate increases dangerously during exercise. ideas?

What does that mean?: Your "heart rate increases dangerously during exercise" Who says it's dangerous? How fast is it? It may be nothing, it may be something. Only way to know is go to a doctor and check it out.

Palpations: You may have developed an arrhythmia. Get checked out by a cardiologist

See a doctor: I am a pediatric cardiologist. The other responses here are all helpful. How do you know the HR increase during exercise is dangerous. And I am assuming the hole closed on its own, but want to confirm. If you've had heart surgery or a catheterization, you may be at an increased risk of developing a heart rhythm problem. In any case, I strongly suggest you see a cardiologist.