One my 3 yr. 8 month job in FL, I was working 6 12s for 14 months towards the end and I quit exercising and walking. I started to get an irregular heart beat especially at the end of the day when I was tired. After that job ended and I came home I started exercising, got my walking routine back up to a 50 minute as fast as I could maintain walk 3 times a week, and lost about 25 lbs. No more irregular heart beat after that. It's amazing what exercise can do for you. The 50 minute rapid walks also reduces my cholesterol levels substantially. I'm 70 now and if I don't exercise, I will turn into a vegetable pdq.