I bought a heart rate monitor today. Great, I thought, will improve leaps and bounds from today. But, tapped in my max and min according to the instructions - it said do 226 minus my age (37!)for the max reading and the lower reading you took from a chart, got halfway down the street and the flipping thing was bleeping like I was about to have a heart attack! Wasn't even out of breath! In fact, to stay in the zone, all I could do was walk! I've been what I call running, since April. Can run for 30 mins - get out of breath, but thought that was the idea! Have I been wasting my time and doing myself more harm than good?