Hello. Thank you for asking on HCM. I read your query. I understand your concern. During physical activity, heart rate goes significantly high and it is considered a normal event, the formula being 220 - age. In your case, due to strenuous activity, it goes up to 204 beats per minute. However, if this is a figure seen while resting, it is not normal, since the normal heart rate is 60-100 beats per minute, and in highly trained athletes it is considered normal down to 48 beats per minute. Now, this may have been a totally benign and harmless, one-time episode, that can be elicited even in physiological states (such as, anxiety, fear, stress or menstruation). However, I would recommend that you should obtain an EKG, since there are some genetic syndromes that are found in teenage years and mandate prompt treatment. I am absolutely not saying that this is the case. Even in this state where my index of suspicion is very low, my opinion is that you should get an EKG done and consult a cardiologist. I hope I was helpful. Best regards.