Day 1
Do your fave cardio (swim, bike, run, Spin) for 45 to 60 minutes at a level 3 or 4. (On a scale of 1 to 10, 1 is the effort it takes to ride the bus and 10 is the effort it takes to throw the bus in the air.)
More: 10 Quick Cardio Moves
Day 2
Give it your all! Aim for a level 8 or 9—that point at which you hate every second—for 30 seconds. Back off to a level 4 for 60 seconds to catch your breath. Repeat 10 to 20 times.
Day 3
Just as on day 1, stay at level 3 or 4 for 45 to 60 minutes. Go for a quick-clip walk, or think outside of the blah-blah cardio box—take a fun class like Hoopnotica (hula hooping!) or grab your honey and salsa.More: Benefits of an Indoor Fitness Class
Day 4
Ahhh, a day off! Kick up your heels and let your muscles recover and repair. You're also allowing your body to replenish its all-important sugar stores (energy), so you're fueled up for tomorrow. Rest
Day 5
Think of this workout like doing a 5K and gunning for your fastest time. Aim for a level 5 to 7, and stick it out for 20 to 30 minutes. Put on your sneaks and run or get your cycle on.
Day 6
By now, you know the drill: Do 45 to 60 minutes at level 3 or 4. Tell your bestie to meet you for a jog, or take your pooch for a speedy walk. Biking to the farmers' market counts, too!
Day 7
Push it, push it, push it! Hit it hard (level 8 or 9) for 30 seconds. Relax at an easy pace (level 3 or 4) for 60 seconds before you go, go, go! Repeat 10 to 20 times.
More: What is Interval Weight Training?
Stay in shape in a fitness class.