Get Fit in 90 Days: Week 1 (The Plan)

Since this is your first week, the plan is to ease into things and start the month off right Goal: To simply put in the time. Plan ahead: Saturday (see below) will be a class of your choice. Start looking for one now before time runs out!

Wednesday: Cardio Session

Start the day off right with a workout. Set your alarm a half hour earlier than usual, and get your workout in first thing in the morning. This will jumpstart your metabolism for the rest of your day. Put in 30 minutes on a cardio machine of your choice—treadmill, elliptical, or stationary bike, Or, if you're game, head outside for a walk, jog, or a run! This is your choice. Remember: Your goal today is to simply put in the time and get that blood flowing and those calories burning!

Thursday: Quick Full-Body Circuit

At what time you choose to do this is your choice. If the morning worked for you yesterday, set that alarm again. If the evening is better, do it sooner rather than later so you don't put it off and run out of time. Here's your circuit: Five-minute warm up (jog, jumping jacks, or imitation jump rope in place), 20 squats, 10 push-ups (on knees or toes, whichever you can do with the best form), 10 lunges on each leg, and 15 tricep dips. (Click here to learn how to do these exercises, or watch the quick how-to video below!) Repeat this circuit three times through, with no more than a minute or two of rest between each.)

Friday: Cardio Session

It's still your choice: Treadmill, elliptical, stationary bike, or head outside for a walk, jog, run, or a bike ride. This time, however, you'll have an interval plan! After a five-minute warm up, you are going to alternate between feeling comfortable (working at a moderate level—think a 5-6 on an effort scale of 10) and uncomfortable (working at a higher intensity—an 8-9 on an effort scale of 10) to up the intensity of your workout. Work three minutes at a comfortable pace, followed by 30 seconds of an uncomfortable pace. Repeat five times, and then cool down for five minutes. This workout will take between 25-30 minutes to complete.

Saturday: Fitness Class of Your Choice

Work outside of your comfort zone by trying something you've never tried before: Pilates, yoga, Zumba, kickboxing, or spinning. In order to change your body, you have to continue to alter your workout so you don't plateau!

Stay tuned for next week's exercise plan! Since part of a healthy lifestyle is eating right, find out how to ward off mindless munching with these 10 tips!

Sara Haley (sarafitness.com) is a Fitness DVD Personality, Master Trainer and Creative Consultant for Reebok.