Heart rate while running with a HRM

mssgeni

I'm pretty new at running so this might be a dumb question!

I really don't know if I'm pushing myself too little or too much at the gym: I can run for like 7-10 minutes with a heart rate from 170-180... I slow down if I get higher than 180, then I run again for more minutes. I put the treadmill on a high incline sometimes too, and my heart rate is always in the 170's.

What heart rate range is safe for a 25 year old female? While running 180 seems totally fine but sometimes after I slow down I get exhausted. I use a polar ft4 heart rate monitor. I want to lose weight but don't want to lose my time or have a heart attack or something. :L