Hello, are heart flutters during very strenuous exercise dangerous? i've been checked out by a cardio but no stress test before. thx

Heart flutters: Possibly. This requires monitoring, Keep a diary. Perhaps a Holter monitor will be valuable. A stress test may help, too, although you are young. Avoid caffeine and energy drinks.

Perhaps...: Feeling your heart beat fast during exercise is normal, but the term "flutters" would imply some abnormality. A stress echocardiogram will help clear up what's going on with your heart during exercise, and could be helpful if you're embarking on an intensive exercise program.