I am 56 yrs, female, white, wt. 130#. Physically in good shape. Work full time at a restaurant, day shift, prep work. Am on my feet all day, with basically 15 min. break sometimes. I push mow my yard, 3 hours every 5 days and am outside 85% of nice summer days after work, yard work, garden ect. My heart sometimes pounds hard in my chest only when I lay down or am not active. When I get up to do activities, I do not not notice it or feel it. I have no feeling of tightness in chest or any other symptoms. My heart rate was 60 beats per min. after I sat down for an hour after I got home. I sleep at night, eat healthy (cookies and ice cream sometimes) drink only once in a great while. What could be causing this feeling? I have had this feeling for almost a month now. Wow I did not know there was a charge involved.