Faint after exercise

Hello, I'm a young man in general good health. However, lately, during exercise like biking or jogging, I've felt as if I'm about to pass out, only I never do. I read about Long QT Syndrome, or Sudden Death
Syndrome, and learned that a symptom might be feeling faint after exercise. Now, I know I've had through out my life several ECGs, does that mean that if I had Long QT Syndrom I would know it by now? Is an
ECG all it takes? Thanks in advance.

Yes, LQTS would show up on an ecg.

Self-diagnosis is probably not advisable. You really should talk to a cardiologist about your concerns.

For long QT syndrome, yes. However, you should still inform your doctor about your symptoms.

You are welcome.

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