I am doing 2-3 runs a week after weights, only on machine. sadly, I can only run about 12km/h speed for 15 minutes (1 degree for incline), and that is very hard. Pulse gets to mid-170s for last 5 minutes.
Most of my runs are at slower pace around 9-10km/h.
My best ever times were 5km on grass at Flemington racecourse in 18 minutes, and 8km on track (20 laps) in 35 minutes, so I have lost a lot.
However, would like to break 6 minutes for 1500m in next 12 months on track.