Workout #1: 8-minute energy booster
When McMaster University researchers had adults do four 30-second sprints (that's just 2 minutes of intense exercise!) on stationary bikes with easy pedaling in between, 3 days a week, they doubled their fitness capacity (the strength of their heart, lungs, and arteries) after 6 weeks and reported feeling stronger, firmer, and more energetic in just 2 weeks.
Our 8-minute workout, based on this study, delivers the same powerful 2 minutes of vigorous activity but in shorter bouts—15 seconds each — so you can really give it your all for faster results. For variety and to work different muscles, try this routine using the Fat-Blaster Moves from Workout #3.
| Minutes | Activity |
| 0:00 | Warm up, walking at a moderate pace |
| 2:00 | Sprint, running as fast as you can |
| 2:15 | Walk at an easy pace |
| 2:45 | Sprint |
| 3:00 | Walk |
| 3:30 | Alternate 15-second Sprint and 30-second Walk intervals 6 more times |
| 8:00 | Finish |
Workout #2: 12-minute calorie burner
Here's an indoor alternative to the 8-minute routine that delivers the same fabulous results. You can use any cardio machine, including a treadmill, an elliptical, or a stationary bike. The session and intervals are slightly longer (12 minutes total with 20- and 40-second intervals) to allow time for the equipment to adjust to the different intensity levels.
| Minutes | Activity |
| 0:00 | Warm up by going at an easy pace |
| 2:00 | Rev it up, increasing speed, incline, or resistance so you're pushing yourself really hard |
| 2:20 | Take it easy, decreasing speed, incline, or resistance so you're going at a comfortable, moderate pace |
| 3:00 | Rev it up |
| 3:20 | Take it easy |
| 4:00 | Alternate 20-second Rev It Up and 40-second Take It Easy intervals 7 more times |
| 11:00 | Cool down by going at an easy pace |
| 12:00 | Finish |
Workout #3: 20-minute fat blaster
This high-energy plan, based on Australian research, will reshape your body in no time. The simple Fat-Blasting Moves (at right) make it doable almost anywhere. We've matched the interval ratio from the study, but the bouts are slightly longer (12 and 18 seconds) to allow you to transition between moves and still hit your peak effort level to burn maximum fat. Marching in place is an easy way to recover in between. For a challenge, try this routine alternating sprints and walking like in Workout #1.
| Minutes | Activity |
| 0:00 | Warm up by walking around or marching in place |
| 2:00 | Jumping Jacks |
| 2:12 | March in place |
| 2:30 | Speed Skater |
| 2:42 | March in place |
| 3:00 | High Knees |
| 3:12 | March in place |
| 3:30 | Twist |
| 3:42 | March in place |
| 4:00 | Repeat above intervals 7 more times in the order listed |
| 18:00 | Cool down by walking around or marching in place |
| 20:00 | Finish |
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1. Jumping Jacks Yep, the ones you used to do in PE class. Go as fast as you can. |
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2. Speed Skater Stand with feet together, arms at sides. Jump to right, leading with right leg. Left leg follows and crosses behind right foot as you land. Simultaneously reach left arm across body as if trying to touch floor. Repeat to left. Jump side to side as quickly as possible. |
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3. High Knees |
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4. Twist Stand with feet a few inches apart. Hop and rotate knees to right as arms go to left, landing with knees bent. Repeat, twisting in opposite direction. |