Im 53, not a couch potato but dont excercise regularly either. I had been having some tightness and pain in my chest, so i went to see my dr. They put me through a stress test and within 40seconds my heart rate went from 88 to 176. I was only on the treadmill for 5 minutes and my heartrate reached 242, at which tiime i stopped. They said that i have deconditioned heart. My dr wants me to start walking slowly for 15 minutes a day and gradually increase to a brisk walk several times a week for 45 minutes over the next 6 months. I didn't get much explanation about a deconditioned heart. Should i be concerned?