Last August I suffered SUDDEN CARDIAC DEATH. I was brought back to life with an AED. I had to have open heart surgery to replace my aortic valve, and had an Internal Difubulator placed. I use my POLAR to monitor my heart while running. I trust POLAR to monitor my heart rate. My Doctors have me working out under strict guidlines. POLAR helps me monitor the heart rate. I trust POLAR with my life. If it wasent for my POLAR I would not be able to work out. I am training for a half marathon in May!