If a person performs a more streneous work without any health complications then is he out of risk?

I am experiencing rapid and heavy heart beats (palpitations) which lasts for around 20 or 30 seconds and then dies down the beats are so intense that my hand tremble in accordance with the rythem foe nearly 10 seconds.otherwise I am able to carrey on as usual and even walk for longer distances and do fairly heavy manual work.The palpitations seem unaffected when I move about.It makes me feel dizzy.but still I am able to move about.Could this condition worsen.