Interval Training for Weight Loss and Fitness
by Maia Appleby

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The theory behind interval training is this: By mixing bursts of high intensity work with low intensity periods of recovery, you're overloading both the aerobic and anaerobic systems at the same time, getting the benefits of both aspects of training simultaneously. You can realistically get a complete workout in thirty minutes with interval training.

How is it done?
Begin as you would on any other day. Start at an easy pace and gradually increase your heart rate for at least five minutes. You can monitor this by taking your pulse for fifteen seconds and multiplying it by four or using a heart rate monitor (here's a cool one that also keeps track of calories!) When you're sufficiently warmed up, you're ready for a burst of high intensity work. If you're on a treadmill, break into a jog or a sprint, depending on what "high intensity" means to you.

During the high intensity periods, you're decreasing your body's ability to exchange oxygen and carbon dioxide. You begin to feel the "burn" as your body eliminates lactic acid (a toxic by-product) and your muscles begin to lose their ability to contract. You wouldn't physically be able to maintain this level of intensity for long.

When you begin to wear your muscles out, decrease the intensity level to something that you could maintain for a longer period. Don't slow down so much that your pulse dips too low, though, or you will lose the aerobic effect completely. Now, you're in the "active recovery period". Your body's ability to exchange oxygen and carbon dioxide increases and it can deliver nutrients to your muscles. The burn goes away and your breathing and heart rate slow down slightly. You have completed one cycle.

Repeat this process of maxing out and recovering your anaerobic system for at least thirty minutes. The high intensity periods should be shorter than the active recovery periods, especially at first. You might walk for five minutes and then run for one when you begin to introduce your body to this type of training. As you become more adept, increase the time you spend in high intensity periods. Forcing yourself to sustain long periods of high intensity activity is dangerous, so do use caution and work yourself up gradually.


Why is it good? Here are four big reasons:

1. It saves time. If you normally spend an hour and a half in the gym following the traditional sequence, you'll work yourself just as hard in 45 minutes with interval training. Finding time to exercise is a big problem for (I dare say) most people. Here's a great solution.

2. It's a great way to get beyond a plateau. I'm by no means claiming that interval training is better than the traditional, tried-and-true warm-up, weight training, cool-down sequence, but when you stop seeing improvements in your physical condition, it's time to do something new and different. Throwing a couple days of interval training into your exercise regimen each week tells your body that it's time to get over the plateau and make additional progress.

3. It combats monotony. Once a routine gets boring, you might decide to do different weight lifting exercises or change around your aerobic activities. You might stop using weight machines and switch exclusively to free weights. Interval training can help you during the transition period between one exercise program and another. It's fun, and the time flies by during each session, because you're working in cycles of high and low intensity work instead of spending a long period of time at any one activity.

4. It's easy! You can do an entire workout without moving from one spot. You set your own rules, using your body's cues, so you feel completely in control of the workout. There's no counting involved and the time seems to go by much more quickly. 

How can it help me lose weight?
By challenging both you aerobic and anaerobic systems simultaneously, you're improving your body's ability to burn calories by leaps and bounds. You're adding new muscle, which speeds up your metabolism of fat in general. You're getting an aerobic workout that burns lots of calories. You're pushing yourself beyond any plateaus that you may have hit doing the same thing over and over again. Your body is becoming a more efficient fat-burning machine.

What activities can I use for interval training?
The possibilities are endless, but the most practical are probably walking/running, other cardiovascular machines like stair steppers, elliptical trainers and stationary bikes, aerobic exercise, water exercise and things like that. You could even incorporate it into jumping rope or a sport like racquetball. If you want to be creative, you can really make fitness fun.

How often should I do it?
If you're a beginner, throw in one session a week, along with your normal routine. If you're more seasoned, two or three times a week is great. This is a demanding form of exercise, so use common sense and listen to your body.

When you're finished with your workout (and you'll be surprised at how quickly you get out of the gym doing this), your muscles have been taxed in a brand new way and need to be stretched. Don't skip this part! You'll feel great when you leave, and your body will thank you by improving its condition to prepare itself for the next time