When training for two consecutive days, there are different goals for each day. The goal for the first day is to verify your own running condition by jogging and prepare your body for the second day. Run at your own pace and don't exert yourself on the first day. Then, run at a fast pace on the second day.
If it is too demanding to train 4 days a week, you can change your training program to 2 or 3 days per week by creating a new plan.