Hi, i'm a 38 y.o. female that has been generally sporty and healthy all my life. After getting a hear rate tracking watch last year, I discovered my resting heart rate was around 53, which is good. When I run though (i mainly run short distances, like 5k and less when less frequent), my heart rate regularly goes up to 160-180 sitting in the top zone, pretty much soon after I start the run. I do not get this while biking. I REALLY don't like running slowly but I did test what a slower run could do to my heart rate, was still up in the 150s. My usual pace is around 6:20/km. Any idea on why and how i could get my heart rate down (is it really an issue?) - i just freak out when I see it's always in that top zone. I feel fine otherwise.