LifeFitness Treadmill, 1.0 incline, 6.5 MPH run speed/3.8 MPH walk speed: 5 intervals of 3 minutes running and 3 minutes walking. I test heartbeat by grabbing the bar 40 seconds before the run begins and immediately when it ends. BPM was 140, 140, 149, 150, 152 at the beginning of the runs and 164, 172, 177, 182, 185 after. This is a 13:49 minute, 1.5 mile pace.
I might still do the fast stuff on the other two days, but not nearly as long, to slowly push up my VO2 max. We'll see.