Always get heart palpitations when im running or doing exercises like my heart skips a beat then beats hard for a second. How to. Stop. This?

Medical check up to . Palpiations are often caused by irregular heart beats what you describe is very likely due to extra beats which can be best confirmed by your doctor who will likely do an ekg to confirm the nature and degree of abnormailty. In young people this can be caused by excess of coffee use or any caffeine containing drinks like coca cola . Alcohol can also bring them on.
Palpitations. Most often what you describe is benign and requires no treatment just reassurance. Your doctor can check you to be sure what your situation is. In the unlikely case some abnormality is present, dr. Can deal with it for you.