The 2,500-Calorie Workout: Fight Fat Faster

Workout 3: Running Intervals

Points Earned: 4 points, (40 minutes; 400 calories)

Indoors: Do the following two groups of intervals on a treadmill, adjusting the incline or speed to suit your fitness level.

Group 1:

3 minutes, 5 percent incline, 5 mph
2 minutes, 5 percent incline, 5.5 mph
1 minute, 5 percent incline, 6 mph
1 minute, 0 percent incline, 6.5 mph
Do complete series three times

Group 2:

3 minutes, 10 percent incline, 5 mph
2 minutes, 10 percent incline, 5.5 mph
1 minute, 10 percent incline, 6 mph
1 minute, 0 percent incline, 6.5 mph
Do complete series twice

Cool down: 2 minutes, 0 percent incline, 3 mph

Outdoors: Jog for 8 minutes, gradually increasing pace as you warm up from RPE 3 to 6. Find a moderate hill and do hill repeats for 15 to 20 minutes: Break the hill into sections: long (all the way to the top), medium (halfway up) and short (one-quarter of the way up). Do 5 to 6 segments each of long, medium, and short repeats. Go hard as you climb (RPE: 8 or 9) and recover on the way down (RPE: 1-3). Finish with 8 more minutes on flat terrain, gradually tapering RPE from 6 to 3.