If you've got an hour, here are two treadmill workouts to try. Wasilewski, who designed both workouts, calls the first one the "No Excuses" routine because it delivers maximum results for the time investment. The second workout is an interval trek, designed to boost cardiovascular endurance.

The “perceived exertion rate” in these workouts is a scale of 0-10 used to measure the intensity of exercise. For example, 0 (nothing at all) is how you feel when at rest, while 10 (very, very heavy) is how you feel after extremely strenuous exercise.

No-Excuses Routine
Start on the treadmill:
Time Speed/ Intensity Incline Perceived Exertion
5 min. 3.5 mph - warm-up 1% Level 2-3
1 min. 4.5 - speed walk/run 6% Level 6
2 min. 3.5 - walk/slow jog 4% Level 4
1 min. 4.5 - speed walk/run 6% Level 6-7
2 min. 3.5 - walk/slow jog 4% Level 4
1 min. 4.5 - speed walk/run 6% Level 7
2 min. 3.5 - walk/slow jog 4% Level 4
1 min. Slowly take it down to stop. 1% Level 2-3

Move to the floor:
• Do one set of 30 overhead shoulder presses with dumbbells while alternating squats.
• Do one set of 30 bicep curls with dumbbells while alternating lunges.

Return to the treadmill:
Time Speed/Intensity Incline Perceived Exertion
1 min. 3.5 mph - walk/slow jog 4% Level 4
1 min. 4.5 - speed walk/run 6% Level 6-7
1 min. 3.5 - walk/slow jog 4% Level 4
1 min. 4.5 - speed walk/run 6% Level 7
1 min. 3.5 - walk/slow jog 4% Level 4