Sizzle Calories in 18 Minutes

I'm going to try this interval workout I found on Yahoo Health:

Whenever I feel like I want to get a little lighter (usually because my jeans are feeling a little tighter), I work intervals into my routine.

Intervals are one of the fastest ways around to shed fat. Women who spent 20 minutes mixing sprints with jogging lost three times the fat off their legs and butt in 15 weeks than those jogging steadily for 40 minutes, a study from the University of New South Wales in Sydney finds. Burn triple the fat in half the time? Bring it on!

To try intervals, do this speedy slimming routine up to six days a week. Pair it with your toning session or do it solo, for results guaranteed to amaze you. Hop on any cardio machine you like for the time allotted and the exertion level noted (1 is the easiest and 10 is next to impossible).

Warm up for 4 minutes at a level 3.
Sprint for 30 seconds at a level 7.
Recover for 90 seconds at a level 4.
Sprint for 30 seconds at a level 8.
Recover for 90 seconds at a level 4.
Sprint for 30 seconds at a level 9.
Recover for 30 seconds at a level 4.
Sprint for 30 seconds at a level 7.
Recover for 90 seconds at a level 4.
Sprint for 30 seconds at a level 8.
Recover for 90 seconds at a level 4.
Sprint for 30 seconds at a level 9.
Recover for 30 seconds at a level 4.
Sprint for 30 seconds at a level 7.
Cool down for 3 minutes, 30 seconds at level 3.

Want even more workout plans to help you lose inches and tone up? Go to Self.com for The Great 1-Month Slim-Down, where The Biggest Loser's Jillian Michaels will coach you through moves.