<s>[INST] I am a chain smoker person.......... on Jan 2012 I join gym,but after 5 months I leave doing gym.........after that at the end of june I feel irregular heart rate.After that I again join gym to get over from this problem....but I haven't yet feel any improvement.....can u plz tell me what is the reason behind it? [/INST] Hi,Irregular heart beat could be of many reasons. Do you even feel it during your gym or only afterwards ?You should get few tests done to know the reason of irregular heart beat. Kindly get ECG and Holter 24 hour test initially to determine the cause.  Let me know in case of further queries. Dr Vishesh Rohatgi, MD </s>