So, you’ve got through the first week of our four-part plan. Now, take your workout to the next level

There are several benefits of walking, but if you incorporate interval training – or varying your pace – into your fitness routine, you’ll reap even more rewards. Interval training will help you burn a greater number of calories and raise your heart rate more than strolling along at a constant pace. It will also make you work harder and you should notice an improvement in muscle tone as well, Josh Salzmann, iVillage’s fitness expert says.

Interval training will break up the monotony of each workout and – if you do it first thing in the morning on an empty stomach for 30 minutes – jumpstart your metabolism for the entire day. You’ll also burn fat more quickly, as the calories stored from the night before will be used up soon after you begin exercising. And even though walking is easier on your joints than high-impact sport, you’ll still enjoy some of the benefits of workouts like running and aerobics because interval training will also raise your heart rate.

The guidelines of our interval workout are exactly that – a general guide – so be sure to listen to your body and use common sense when exercising. If something doesn’t feel right, stop doing it, and don’t forget that rest and proper nutrition are essential for a successful fitness routine. If you don’t allow your tired muscles to recover, no amount of exercise will give you the results you want.

Try our sample workout plan below, but take it easy this week, especially if you are still getting used to a regular fitness regime. Salzmann suggests starting slowly and increasing your intensity to a maximum of level six no matter how fit you are. For those of you who are active but trying to get in better shape, hold your higher intensity levels for longer, assuming it doesn’t hurt your joints. Good luck.

Monday: Pre-stretch for your usual three- to five-minute warm-up to get your joints and muscles ready to work. Begin walking slowly, then increase your pace until you feel uncomfortable, but not so pushed that you’re out of breath. Walk at this moderate pace for two minutes, then speed up for two minutes. Next, slow back down to your original pace for two minutes, then increase your pace slightly higher than your last high-intensity interval pace for another two minutes. Keep alternating these intensities, going higher each time, until you get too tired to go faster. At this point, keep varying your pace every two minutes, but start at the lower intensities you tried at the beginning of your workout. As long as you’re interval training, you are benefiting, and there is no reason to push yourself to a stage where you’re totally winded. Do this workout for 30 minutes, then warm down for three to five minutes.

Tuesday: Rest

Wednesday: Increase your high-intensity interval duration to three to four minutes (as opposed to two minutes) if possible.

Thursday: Rest

Friday: Take your high-intensity interval duration to five or six minutes (instead of four minutes) if possible. Alternating intensities is the key, so remember, you don’t have to maintain a high pace for five to six minutes if this is too much.

Saturday: Choose strength training or another kind of workout like Pilates or yoga to break up your routine.

Sunday: Rest

For the rest of the walking series, check out Josh's week 3 powerwalking workout and his week 4 walk/run workout.