Heart rate and Turbofire

Nita_Bita

I have a polar hrm. My target heart rate zone on my monitor is 129 - 169. I'm guessing that the watch has gotten this zone by using my age (24), weight (171 lbs) and height (5'4). What I'm concerned about is if it is safe for my heart rate to go over this zone while working out? Will my heart be stressed out? My heart rate usually gets up to 175 - 185 during the regular portion of the workout (not including the HIIT intervals). It usually depends how into the workout i am. I don't have any chest pains while at that heartrate or feel like i can't breathe. Is it ok for me to stay at this interval or should i just take it really easy and stay between 129-169? I don't feel like i'm really working out unless my heart rate is above 170.