Why do i get heart palpitations upon exertion?

Tough to say...: There are certain rhythm problems that only come on with exertion. Palpitations however, are an unnatural awareness of your heartbeat, so even being severely deconditioned can do it. I'd find a cardiologist or cardiac electrophysiologist and have them run you on a treadmill while wearing ekg. If that doesn't work, we'd get you an "event monitor" to record the palpitations.

Challenging scenario: Which requires further testing & evaluation...How severe are symptoms?