Mix and match the workouts below for a total of five to six cardio sessions a week. The mix of routines will help your body burn fat more efficiently and build endurance. Combined with our strength workout, you'll see pounds melt away!

In each cardio workout, you want to move among four zones that represent how much effort you’re putting in. Here’s how to tell which zone you’re in.

Zone 1 = Easy
Zone 2 = Challenging but comfortable (you’re breathing
hard but could still hold a conversation)
Zone 3 = Challenging and uncomfortable (you’re breathing hard, difficult to hold a conversation)
Zone 4 = Breathless, really hard!

New-mom modification: If you’re a new mom (or are very out of shape), keep your intensity easy to moderate. Avoid Zone 4 until you’re three to four months postpartum.

Intense Interval Bursts (30 minutes)
Do this while walking outside on a long, steep hill or on the stairs, treadmill, or elliptical trainer.
1. Warm up with 2 minutes in Zone 1, then 3 minutes in Zone 2
2. Uphill, 1 minute in Zone 4
3. Downhill, 1 minute in Zone 2
4. Repeat steps 2 and 3 nine more times
5. Cool down with 5 minutes in Zone 1

Middle-Ground Mix-It-Up (40 minutes)
Do it as a walk or run outdoors or on the treadmill, bike, stairs, or elliptical trainer.
1. Warm up for 5 minutes in Zone 1
2. Spend 8 minutes in Zone 3
3. Do 2 minutes in Zone 2
4. Repeat steps 2 and 3 two more times
5. Cool down with 5 minutes in Zone 1

Long, Strong, and Steady (60 minutes)
Bike, hike, walk, or skate outside, or mix it up at the gym by choosing three cardio machines and doing 20 minutes on each.
1. Warm up for 5 minutes in Zone 1
2. Work out 45–50 minutes in Zone 2
3. Cool down for 5 minutes in Zone 1

Chris Fanning

Even if you only log a few miles here and there, you can prep for a 5- or 10K in one month (or a half-marathon in just eight weeks, if you’re already a seasoned runner). With a simple training plan from Olympic medalist Deena Kastor and her husband, ASICS running coach Andrew Kastor, you’ll rock daily workouts customized for the race you choose, make it to the finish line, and get a slamming tone-up along the way.

If you’re able to run a mile without stopping, you’re ready to train for a 5K. If you can cover more like three miles at a time, you can totally handle a 10K. And if you have no trouble laying down five continuous miles, a half marathon is well within reach (you’ll just need a little longer to train). Whatever you choose, you’ll find a the right training schedule below, but don’t freak if it doesn’t fit your schedule exactly. "It’s okay to switch things around a bit within each week to make it work," says Andrew Kastor. "Just don’t do hard workouts back to back." 

Worried you won’t be able to keep up the enthusiasm? Our training power duo can help there, too. "What got you out of bed and into your running shoes last year (or even last month) won’t work forever, so change it up when you feel your motivation start to flag," Deena Kastor suggests. Post an inspirational photo on your bathroom mirror, download a hot new playlist to your iPod, or come up with a new mantra. Her latest, taken from a U2 song, says it all: "It’s a beautiful day, don’t let it get away."