I'm wondering how one should control the speed of running. Currently my running speed for a 'long' run goes like this:
1st-3rd minute: Starting an 9km/h going down to about 8km/h. I actually try to run slower, but find it difficult and awkward.
-40th minute: From a little over 8km/h slowly decreasing to 7km/h.
-45th minute: Slightly increased speed (7.5 to almost 8km/h) due to 'end of run motivation'
Heart rate is at about 140bpm after 5minutes and increases slowly to about 150bpm after 40minutes, going to 155-160 in the last 5 minutes.
Question: Should I change anything on the speed profile in order to be able to run for longer time at about the same average speed or a little faster. This is not about the training effect of the pace/intensity, but about the ability to maintain the average speed for longer / increase the average speed for a given distance. Basically as if the run would be a competition.
I find it a little strange that I ran so fast in the beginning, although I actively try to go slow. Is this ok, or should I try harder to go slow?
Should I go slower after the first 5 minutes in order to keep my speed until the end?
Background: I picked up running 5 weeks ago and my longest run was (this morning) 6km in 45min as described above. My medium scope goal is to run 8km in an hour. My maximum heart rate is 180bpm.