Notes
Progressive tempo.
Started first 15 minutes at around 6 mph (10min/mi)
Then gradually increased to 8 mph (7:30/mi), but that was a bit uncomfortable, so dialed back down to 7.5mph (8 min/mi)
Stayed at 8min/mi for a while. It was a confortablly hard zone for me, HR was around 155 for the last 30 minutes.