Doing interval exercise, in which you alternate short bursts of intensive effort with easier recovery periods, not only helps you lose weight (and keep it off for the long haul), but it also strengthens your heart and lungs and improves your muscle metabolism, boosting your “good” HDL cholesterol and helping your body handle insulin and sugar more efficiently. Dr. Arthur Agatston, creator of the South Beach Diet, recommends a minimum of 20 minutes of interval exercise — like interval walking outdoors or in — every other day.
Don’t worry if you’d rather hit the gym (or work out in your home) than head outdoors. You can do your interval-training program on a treadmill, a stationary bike, or an elliptical machine by following the intensity levels described here.
Also keep in mind that on days when you’re not doing interval training, you should do some core-strengthening exercises to target the vital muscles in your back, abdomen, pelvis, and hips. These are the muscles that are critical for posture, flexibility, balance, and stability. And on superbusy days when you can’t find time to do either, get up from your desk and work in a short recreational walk. Any exercise is better than none and the fresh air will do you good!
Interval exercise, as Dr. Agatston describes it in his South Beach Diet Supercharged book has four levels of intensity. Begin at an Easy Pace and work up to Supercharged as your fitness improves.
Pace: When you’re
working at a low level of intensity, you’re constantly moving, but you can
easily carry on a conversation with a friend. This is the pace at which you
will do your warm-up before beginning the actual intervals — and also
your cool down when you’re done.
Pace: When you’re
exercising at a moderate level of intensity, you’re working at a brisk pace.
You are breathing faster and can still carry on a conversation — but
doing so is more difficult than at an easy pace.
Up: When you’re revved
up, you’re really moving! You’re a bit short of breath, and it’s hard —
but not impossible — to maintain your pace. You should have difficulty
carrying on a conversation at this level of intensity.
- Supercharged: When you’re exercising at top speed, whether it’s walking or doing some other form of interval exercise like swimming or biking, you are truly supercharged! You won’t be able to sustain the pace for long, but as you get fitter, the pace that once tired you out will become relatively easy and even your supercharged pace will get faster.
As your fitness improves, you should adjust your speed, resistance, and/or incline (try some hills if you’re walking or biking) to match your new level of ability. Overall, speed is better than resistance. Increase resistance only to add intensity when you have achieved all that you can at maximum speed.