Workout Update: 645 Cardio/MBF Day 4

Day 4 was another core circuit day in MBF and the 15-minute cardio workout from 645. So, today was heavy on Cardio, which was kind of nice because the cardio work is getting a bit easier. The MBF workout was similar to Tuesday's workout in that you alternate cardio blocks and core blocks. And, each of the core blocks had two sets of Mountain Climbers, so you end up doing cardio the entire time.