abnormal Rhythm

[johnwinchester]

i'm so much worried while i'm writing that one of these forceful very strong heart beats will comeback, i was walking in the sun for 3 hours at least it was so hot and i was so exhausted and suddenly very strong heart beat came i put my hand on my chest and my heart rate was so elevated then suddenly another one came strong, then rapid heart rate, then the third one hit i was standing putting my hand on my chest and felt like i'm going to die, this all happened in 10 seconds before my heart comes back normal, but these single strong beat kept coming for the next week at rest and when walking, i went to a cardiologist and he didn't catch anything abnormal, please can someone explain why did this happen? or what exactly happened, i run for 12 km everyday and i'm so afraid this will happen again.

[ThatSuperGuy]

That is heart palpitations. It is very common.