By Steve Edwards
There are a lot of contradicting ideas—many of them misconceptions—about the best way to reshape your body. This is largely because there are a lot of trainers out there, each seemingly espousing a different fitness philosophy. In this article, we'll examine an assortment of training strategies, bust a myth or two, and explain why interval training is generally the most efficient way to improve your fitness level.

Having just launched TurboFire, we dusted off this article that was first published when INSANITY came out. Since most Beachbody programs use some type of interval training, the information we lay out here is also a perfect lead-in to TurboFire. We'll go into more depth about that program next week. Consider this Part I, your introductory course on interval workouts.
What is interval training?
Basically, you're interval training any time your workout includes a set where you perform at your maximum level for a given amount of time, followed by a lower-intensity set; this sequence is then repeated to achieve a cumulative effect. An interval can be a set of curls, a dance move, or anything that tires you out over a given length of time. Intervals can be short and hard, or long and easy, but they're all intervals, just as long as there's some cumulative effect—you get more tired as you go. All interval workouts aren't the same, though; the duration and intensity of the intervals are what define the workout.
Conversely, aerobic training is when you maintain a steady output at a low-intensity level over the course of the workout. Beachbody does offer some workouts that do this, but they're generally either for recovery or for the second daily workout of a doubles program. This type of workout helps your aerobic efficiency, but does very little for changing your body.
The myth of the fat-burning zone
It's impossible to approach this topic without debunking the term "fat-burning zone." You often hear uninformed trainers recommend that their clients reduce the intensity of their workouts so their bodies will burn more fat. In reality, all these trainers are doing is lowering the overall effectiveness of their clients' programs.Here's a quick explanation of the fat-burning zone. At an aerobic pace (see above), your body utilizes stored body fat as fuel to save its preferred fuel (stored blood glycogen) for more pressing matters. This sounds great, because you're burning body fat. However, you're burning it at a very slow rate.
During higher-intensity work, your body turns to a limited supply of blood glycogen (often called blood sugar) for energy. While your body is burning glycogen rather than fat during this more intense period, it's also breaking down more body tissue. "Breakdown" is a negative-sounding word for a good thing, because while it's happening, your body produces more hormones and increases its metabolism to repair the breakdown. As the tissue repairs itself, it builds more muscle, so the next time you do a stressful workout it won't be so taxing. This process of adapting to intense exercise is where your body makes the most rapid change.
Continually building on this process is called "progressive overload." By continually adapting to stress, then adding more stress, either with weight, speed, or intensity, you increase your body's fitness so it's actually burning body fat for fuel as you rest. Interval workouts should be a key component in every phase of your training.
Techie science made simple
Asked what separates serious athletes from recreational athletes, author and fitness trainer Steve Ilg replies, "Intervals." But because "intervals" is an umbrella term for training that targets many different energy systems, Steve's answer is somewhat cryptic and requires further explanation. At the same time, however, it's pretty accurate. Recreational athletes like to train within their comfort zones. Interval training, regardless of the targeted intensity level, always forces you out of your comfort zone. And you have to be willing to leave your comfort zone if you want to see significant changes in your fitness level.
Interval levels can change dramatically. For example, HIIT (High Intensity Interval Training) workouts are very short, sometimes lasting only seconds, and are completely anaerobic. Marathon runners will often run for one- or two-mile intervals, which can take many minutes and are obviously somewhat aerobic. The reason for the varying intensity of intervals is to train different energy systems in the body. These are defined by terms you may have heard, like anaerobic threshold (AT), VO2/max, etc., but we don't need to go into that level of detail yet. For our purposes here, we'll give you the "101"-level course in what you need to know:
- LSD. Not the hippie drug from the 60s, but rather "long slow distance." This isn't an interval; it's a term you're especially likely to hear if you know or are a runner or cyclist. The purpose of LSD is base-level aerobic conditioning. As I said above, this approach isn't really applicable for making significant body changes, unless you do it for a very long time. Yet many trainers still recommend it. I think this is primarily because their clients won't complain about doing 30 minutes of easy exercise.
- Sports-specific intervals. These can be anything, like the two-mile example above. Interval training exists for all athletic endeavors. Since it's targeted for sports performance, we won't discuss it. You'll learn plenty about it when you join a local group to train for a triathlon, or other activity or event.
Weight training intervals. All weight training could be considered interval training, but traditionally, you rest so long between sets you don't get a cumulative effect. All Beachbody weight training is done interval-style, which we call circuit training. During these workouts, you move from body part to body part without much rest between sets, so the workouts don't just target muscle building, but also improve your cardiovascular fitness. P90X and ChaLEAN Extreme are good examples of this kind of training.
What defines these circuits is your targeted number of repetitions. A low target using more weight will create muscular hypertrophy, or growth. A higher number of reps limits muscle growth (although you do still get some muscle growth) and gives you more cardiovascular improvement.- Cardio intervals. These are what most of you probably think of when you think of interval training. First, let's define the difference between "cardio" and "aerobic." Cardio means heart, while aerobic means oxygen. Aerobic training is most easily defined by the word "easy." (It's really defined by training below your anaerobic threshold, but let's dispense with the science talk.) Cardio, however, is any and all training that affects the heart, so it can include aerobic training, but also all the high-intensity training associated with intervals.
High-intensity cardio intervals are performed in something we call "heart rate training zones." Cardio intervals target these heart rate training zones for various periods of time. When you design your own interval workouts, you have to do this for yourself. When you have a trainer, he or she does it for you. This is why we at Beachbody always have test groups to make sure our workouts train you in your proper zone. That way, all you need to do is follow along.
Interval lengths
In general, the longer the duration of the interval, the easier the workout. Some interval sessions have long and moderate intervals with short aerobic breaks. Others have short, difficult intervals with long aerobic breaks. Two interval systems that buck this trend are HIIT and INSANITY's MAX Interval Training. Both feature high-intensity intervals with short breaks, and both systems are very effective for creating rapid body composition changes. But due to their intensity, it's vital that you only do HIIT or MAX Interval Training for short periods of time as part of an overall program—like INSANITY, or Beachbody's new program TurboFire—that includes other types of workouts as well.How to incorporate intervals into your workout program
As with every other aspect of fitness training, the type of interval training you start with should be based on your current physical condition. If you aren't very fit, you'll want to start with a very basic interval program (which will still feel plenty hard). Workouts like Slim in 6's Start It Up! or Power 90's Sweat Cardio 1–2 are good introductory interval sessions. If you're in doubt, start slowly. It's easier to increase your workout's intensity than to go backward. Intervals are the most effective way to see quick results from a workout program. If you're not doing intervals in your current workout regime, try adding some. If you're already doing intervals, maybe it's time to step up to the next level. You might just be amazed by the results.


"I had begun to study HIIT, or High Intensity Interval Training, which is short workouts that feature ultra-high intensity intervals," says Chalene. "I was using this in my classes when we created the Fat Blaster workout as part of Turbo Jam's continuity program. It was the hardest video we had done, and I didn't think people were going to like it. In fact, it almost didn't make it into the rotation. But then it turned out to be everyone's favorite." This meant, essentially, that TurboFire was on.
Chalene adds enthusiastically, "I think the music is 100 times better than Turbo Jam! Music is so important to me because with good music you don't have to find the motivation; it's there. It makes classes so fun that you don't notice how hard you're working out. It's so much easier sprinting to the right song than a random soundtrack.We had more of a budget and more time with the producers so we could get the music perfect. I had more of an influence over the process and was there every day. I wrote the lyrics. I controlled where the energy needed to build for the workout. This is why it took so long to get it done. Training this hard to OK music was totally not OK. I needed it to be off the charts, un-friggin'-believable, amazing music!"
This colorful salad can be served as a first course or a main course. With ingredients like tomatoes, green beans, cranberries, walnuts, and more, this salad looks almost as good as it tastes.
Sushi: Fish wrapped in rice and seaweed. Not a diet food? Yep, that's right. It's not always as "light" as it seems. Some sushi has calorie levels so high it might just shock you.
Granola: When you're having granola, you might think, "It's healthy. The fiber and all those little pieces of dried fruit are so good for me." Truth is, although it's got good stuff in it, it also packs in the calories.
Pumpkin-Flavored Baked Goods: Pumpkin is nutritious, but these baked goods can be a dieting disaster. Like bran, pumpkin has lots of stuff that's good for you. So if you see pumpkin on a baked-goods label, it's easy to think you're eating something that's lower in calories. Not the case, though: Pumpkin doesn't mean diet food.
"Healthy" Salads: That's what some restaurants want you to believe in their "lite" section of the menu. It must be diet-friendly, right? Not always.
How much skin does it show? Are you currently having a "wish I were out of this body" experience? I've been there, especially at the start of a fitness program. So I understand the desire to cover up in big, baggy workout wear. Bare midriffs aren't the best look for all of us. But keep your eyes on the prize.
How much support does it give? When working out, you want to focus on how you're moving your body, not on how it wants to move on its own. If there's more of you to love in certain areas, you may be happier in workout clothing that provides some restraint. Some clothing companies, particularly ones geared toward women, rate the bounce-to-the-ounce allowance of their sports bras. If you're doing a high-impact activity that includes lots of jumping (plyo fans, holla!), opt for more support.
And the most important tip of all? WEAR IT. Whatever type of workout clothing you prefer, put it on. Push Play. And get your body moving. Pretty soon, you'll see results that make all this jumping and sweating worth the trouble—when the clothes you picked out begin to fit differently. And that's something exciting to work for.
I eat plenty of "good" carbs. First, I make sure that the majority of my carb intake consists of the so-called good carbs—oats, brown rice, butternut squash, sweet potatoes, and beans are some of my favorites. I also eat plenty of vegetables, and even fruit (OMG!). These foods contain tons of fiber, vitamins, minerals, and protein, so I get lots of energy-boosting nutrition and I stay full longer.
If I really want it, I eat it. Sometimes a hot-fudge sundae is the only thing that'll cure my craving. So I eat one.
As I get older, I can't get away with eating as much as I used to. So when I've overindulged a few too many times, here's what a typical day of back-to-basics eating might look like:
Nice: Buying low-fat eggnog will save you about 100 calories. Or you could try making your own eggnog from scratch; substitute skim milk for cream and egg substitutes like Egg Beaters for the eggs to reduce the fat and calorie contents. You can also go easier on how much sugar the recipe calls for; it's almost always more than you need.
Nice: You could just have a regular pint of ale. A pint of Newcastle, my favorite, only has 187 calories for a pint. You could toss in a cinnamon stick to make it festive, I suppose. Otherwise, when making wassail, like everything, the best advice is to go easy on the sugar. Not to mention, excessive sugar is one of the main contributing factors to that post-holiday hangover.
Nice: To make it even lower in calories, you could (all together, now) cut down on the sugar. If you use a sweeter, higher-quality wine, you won't have to dump so much sugar in to make it taste good. By using a more full-bodied wine like a Zinfandel or shiraz for your base, you'll get more wine flavor instead of cloying sweetness. Ask your wine merchant what a good wine would be for mulling. Then, let the no-calorie spices flavor the wine, and add a little sugar at the end if you really feel it needs it.
Nice: Probably the easiest way to make this buttery beverage a little more figure-friendly is to add more boiling water and dilute the evil. Or, if you can live without the butter, you can make a hot toddy. A hot toddy is a bit of alcohol, like whiskey, brandy, or rum, with hot water poured over it. You can add other ingredients like lemon juice or spices (nice) or a little sugar or butter (naughty). This should take the chill out of your bones nicely without overinsulating them with weight gain.
Nice: Like almost every recipe, the secret to making things healthier lies in making more of it yourself. As the gift baskets from vendors stack up around the Beachbody® offices, there are lots of packets and tins of instant powders, each one having more sugar than the next. The more you can resist the convenience of the instant sugary powders and mixes, the more you can control how much sugar goes into your drink. For example, for hot chocolate, you can substitute skim milk for whole milk, and add unsweetened cocoa powder or melt in some dark chocolate with a high cocoa content. Then, if you're going to hooch it up, add the schnapps before you add the sugar. Schnapps and most liqueurs already contain enough sugar to effectively sweeten your drink without it being sweet already. Plan ahead, and you can create beverages that are filled with flavor instead of sugar and empty calories.
Sweet potato – Vitamin A: Sweet potatoes have come up a lot in recent articles that I've perused. That's probably because they're freakin' delicious. Growing up in the South, a group dinner could run the risk of being shut down if there were no sweet taters in, at least, a 5-mile radius of Grandma's kitchen. A baked sweet potato (with skin) contains a ridiculous 769 percent of the recommended daily value (RDA)** for vitamin A. In addition to being low in sodium, it also has 65 percent of the RDA for vitamin C. That's right! No scurvy for you!
Milk and cookies – Fiber and vitamin D: Santa leaves a gift for you every year, right? Why not leave him a gift of your own? Instead of contributing to Santa's impending heart attack, why not slide him some heart-healthy food? Give the man a fighting chance. He's already breathing in smoke and fumes from all of that chimney exploring. Instead of those extra-sweet cookies that you usually bake for him, bust out some low-sugar oatmeal cookies. Fiber is his friend. Be his new Rudolph, and guide his sleigh to a new, healthier way of life. Don't forget the glass of milk. Make it low-fat or skim milk. A cup of milk has about 25 percent of the RDA for vitamin D, which is a scarce commodity, and is only naturally present in a few foods. That's like drinking sunshine.
White Russian drink – Low fat: This holiday favorite has been known to give some holiday partiers an early exit. But if you're planning to make a grand exit of your own, you might as well do it with a little less guilt . . . and gut. I've seen White Russian recipes that have as much as 800 calories. Yolki! That's a whale of a drink. While you're mixing that 1-1/2 ounces of Kahlua or coffee liqueur and 1-1/2 ounces of vodka, try using 3 ounces of fat-free half-and-half, instead of that nice, thick whole milk or cream. Also, try substituting the 1-1/2 ounces of cola with a diet cola. That should cut down some of those calories and fat. And as always, drink in moderation. That way, the youngsters won't find you passed out under the tree on Christmas morning, drooling on the circuitry of their video game console.
This colorful salad can be served as a first course or a main course. With ingredients like tomatoes, green beans, cranberries, walnuts, and more, this salad looks almost as good as it tastes.
Want to serve something festive that won't have you looking like Santa in the new year? This twist on a holiday favorite has a great carb-protein-fat ratio that'll help you stay healthy for the holidays.
Hydrate. This is, by far, the most important thing you can do during the winter. When it's cold, it's hard to drink enough water. For one, you don't get thirsty. But even when you are, drinking cold water can cause your body to revolt, creating a catch-22 that can leave your skin dry and itchy. Our bodies are mainly made up of water. Here are some of the roles that water performs:
Exercise. Most of us work out to keep healthy and/or look good in a bathing suit. If that's all you thought exercise did, welcome to the bonus round. Working out also does wonders for the skin by toning, reducing stress, and increasing circulation. Increased circulation means that your blood can deliver oxygen and nutrients to your hide.
Moisturize. Try doing it as soon as you get out of the shower, and do your best to make this a ritual. Post-shower, when your natural oils have been washed off, is a vital time for moisturizing. Even if you're pressed for time, taking a minute to add moisturizer to your entire body is worth it, since your skin absorbs it best when it's warm and damp. You don't have to limit this to once a day—your skin would be pressed to get too much lotion—but after a shower is by far the most effective time.
Take hydrating baths. While soap dries your skin, there are ingredients that, added to a bath, will help hydrate you. Baking soda works if your skin is very dry and itchy, but as a precautionary measure, choosing a hydrating bath substance makes more sense. A perusal of any skin care aisle will provide you with myriad options.
Take your vitamins. Vitamins and minerals do all kinds of things for your skin. Zinc and protein speed healing and reconstruct damaged tissue, as does vitamin C, by aiding the production of collagen—the protein-building blocks vital to all your connective tissue. Vitamin E helps with circulation, which flushes out toxins. Both vitamins C and E deliver antioxidants, which are believed to fight against sun damage, smoke, and the dreaded hole in the ozone layer—although they are by no means a substitute for sunblock and a good hat. To ensure you get all the vital nutrients you need every day, it's a good idea to take a premium multivitamin like
Use sunscreen. Most of us are conditioned to add sunscreen while skiing or going to the beach, but daily sunscreen use on your face and neck should be practiced. Many facial moisturizers have sunscreen as an ingredient. Because they are more expensive, it makes economical sense to have two bottles of moisturizer, one for your face and neck, and one for the rest of your body.
Eat fruit. All the damaging effects of cold, dry air create free radicals—nasty little oxidized molecules that are believed to cause tissue damage at the cellular level. Among other things, free radicals contribute to the development of cancer. The best way to neutralize them is with antioxidants, like the ones you get from many fruits and vegetables, including oranges, berries, leafy greens, and beets. You'll also find antioxidants in green tea and some in tasty items like chocolate. But fruit, which is harder to find during the winter, is the best natural source of antioxidants and has a number of other hydrating and health effects to help keep winter's ill nature at bay.
Humidify. When Mother Nature isn't cooperating, it can make sense to use man-made solutions. Humidifiers come in all shapes, sizes, effective ranges, and prices. From the poor man's solution of boiling a large pot of water to highfalutin units that can make life in an igloo mimic life in the Amazon jungle, the principle is the same: to add moisture into a dry environment.
Skin-friendly couture. Cottons, silks, and other skin-friendly fabrics that glide over your skin can help lessen the irritation of winter. Unfortunately, many traditional fabrics that keep you warm can also make you feel like you're wearing a Brillo pad when the northern winds begin to blow. When you can, layer with something soft as a base.
Author Marianne Williamson has a good point, though. While it's theoretically simple to get your body to do a program like
Even the quickest perusal of this beautiful, instructional coffee table volume on home gardening is enough to make you want to dust off your hoe and overalls and convert your back deck into an organic tomato plot, but be warned: It's not that easy. Sure, veteran green thumb Jimmy Williams and his coauthor, home and garden feature writer Susan Heeger, do a great job at showing you how it's done, but keep in mind that produce gardening, especially without the time-saving aid of hellishly evil chemicals, is a time-consuming passion. You don't get weekends off. If you don't tend to your fruits and veggies, they'll probably die.
Surfers, myself included, tend to take pause when outsiders take on their sport in print. Our attitude is that if you don't ride waves, it's difficult to understand what it's all about, so don't try to tell us about it.
When Kristin Kimball met Mark, the man who would soon become her husband, she was a New York City journalist, scraping along in a typical urban existence. Mark, conversely, was anything but typical. The eccentric, handsome, organic-farming savant with a gift in the kitchen and a penchant for wearing his T-shirt inside-out every other wearing (so that they’d wear more evenly) swept her off her feet. Before she knew it, she'd moved out of her rent-controlled apartment and into a dilapidated farmhouse on 500 acres near Lake Champlain to live Mark’s dream of building an organic, "all diet" farm.
Graduated increase in heart rate and body temperature. If you were to run a 400-meter sprint, it's unlikely you would arrive at the track, pull off your sweatshirt, and suddenly explode onto the track in an attempt to finish in 40 seconds. You'd be wise to begin with a walk and increase to a slow jog, which you would maintain for 5 to 8 minutes. Slowly increasing your heart rate and body temperature in a training activity similar to exercise you're about to undertake allows your heart, muscles, and mind to adapt to the workload you have planned for it.
Graduation to proper training intensity. After you complete your stretching routine, the final step of your warm-up is slowly increasing your intensity to your training level. The duration of this last portion of the warm-up depends on your planned activity and your current fitness level. In the case of your upcoming run, you might go back to your jog and slowly pick up the pace until you're at a run, then perhaps intersperse some sprinting intervals for a few minutes. Then you'll be ready to go for the 400!
Decreasing your heart rate. We've all heard the story of the college student who suddenly stopped at the conclusion of a race, and then dropped to the ground. The lesson to be learned is that your heart needs a gradual return to normal. The length of the first portion of the cooldown depends on the intensity and length of the workout. If you went for a run at 70 percent of your max for 30 minutes, you'd complete a jog for at least 5 minutes, followed by perhaps 2 more minutes of walking. If the workout was longer or more intense, a longer time is needed for your heart rate to slow down.
Decreasing your body temperature. So you've finished your stretch and you immediately jump into a cold shower, or take a walk outside in your sweaty workout clothes in January. Um, no. This is a shock your muscles don't deserve. And yet this happens more often than you can imagine. I can't count the times I've watched ballet dancers finish class in New York City, then walk outside in their tights to smoke a cigarette in the snow. Slowly lowering your body temperature means just that . . . slowly. If you have to walk out of the gym, put on something warm. If you just finished P90X in your living room, spend a few minutes moving around your house before jumping into a warm shower. Slowly lowering your body temperature will allow your muscles to continue to relax, including one very important muscle: your heart.