The point is that if you want to burn more calories, you need to work out with greater intensity. But don’t worry, we’re not telling you this so you feel compelled to get on the treadmill for an hour a day. In fact, we’ve already seen some excellent results with women we’ve put on our 20-minute-a-day Interval Walking program. Not only have they lost excess pounds, but they’ve lost them in trouble spots like the waist and hips.
Studies also reveal that interval training is more effective for normalizing blood sugar and correcting bad blood fats (such as LDL, or low-density lipoprotein, cholesterol, and high triglycerides) than conventional exercise, making it ideal for cardiovascular health. This means that interval training is a wonderful choice for people at risk of developing prediabetes and diabetes. And it’s particularly effective for burning away belly fat, the dangerous visceral fat that is the bane of many men and women in midlife.
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HOW YO-YO DIETING WORKS AGAINST YOUR METABOLISM
The human body is designed to combat adversity. While this was good for our prehistoric hunter-gatherer ancestors, it’s not necessarily good for us when it comes to dieting. Hunter-gatherers faced frequent periods when food was scarce. What saved them from starvation was that during times of famine, their metabolisms switched into low gear, permitting their bodies to run on fewer calories.
Unfortunately, this innate survival mechanism doesn’t help modern dieters, especially those who are impatient and want to take off a lot of weight very quickly. When people go on severely restricted, low-calorie crash diets, they do lose a lot of weight at first. But then the survival mechanism kicks in. Their metabolisms slow down and weight loss stops or becomes much harder, which is exactly what they don’t want to happen.
Furthermore, when caloric intake is drastically restricted, it’s not just fat that’s burned to maintain blood sugar levels and provide energy; it’s also protein from muscle and bone. Muscle requires more calories to maintain than fat does. When we have less muscle, we burn fewer calories, even at rest.
And this is just the beginning of a sad cycle for many people. It’s impossible to stay on a low-calorie, high-deprivation diet for a long time. We just get too hungry. To feel better, we eventually break down and start eating normally. When this happens, we start packing on the pounds, gaining more weight than we carried before because our metabolisms have slowed. When we get fat again, we freak out, go back on the low-calorie diet, and—you guessed it—inadvertently slow our metabolisms even more. The cycle repeats itself over and over again. And we get fatter and fatter.
We call this cycle yo-yo dieting. You lose weight quickly, gain it back again, and then have to lose it all over again, only to regain again—in spades. Each time you yo-yo, you decrease your metabolic rate and ultimately wind up working against yourself.
The bottom line: Deprivation diets don’t work. Gradual weight loss does. By making the healthy food choices on the three phases of the South Beach Diet, you never starve yourself; you keep your metabolism working efficiently; and you lose weight slowly, steadily, safely, and permanently.
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There’s yet another reason interval training is preferable to conventional training: It prepares you better for living in the real world. Consider this. Do you take your training heart rate when you leave the house in the morning and stay at that level for the whole day? Of course not. You’re constantly speeding up and slowing down as you go about your activities, whether you’re getting up from a desk, running for a bus, or chasing after a toddler. Our lives are actually built around interval activities. Therefore, an ideal fitness program should prepare you for the kinds of physical demands you encounter every day. And interval training does just that.
How Interval Training Works
How does interval training work? It switches your metabolism into high gear and increases your demand for energy (calories) so that you burn more calories and fat. Think of your body as a car. When you drive in stop-and-go traffic, you burn a lot more gas than when cruising along at a constant speed. With gas prices so high these days (let alone our desire to use less fossil fuel), that’s the last thing you want to do when you’re driving. But it’s exactly what you do want to do to burn maximum calories and fat during exercise. And that’s how interval training works. Every time you work hard and then slow down, you waste energy and use up calories. And what it’s costing you are those extra, unwanted pounds.
Debunking Those Exercise Myths
Many of you have heard metabolism mentioned in connection with weight loss, but unfortunately, few people actually understand what metabolism is all about. If you want to look great in your bathing suit, fit back into your “thin” clothes, prevent diabetes, and maintain a healthy weight for life, you need to know how to make your metabolism work for you, not against you. So bear with me while I give you a brief lesson on metabolism.
In a manner similar to how your car runs on gasoline, your cells run on a substance called adenosine triphosphate, or ATP, which is made in all the cells of the body. You need energy from ATP to run your body’s systems as well as to perform your day-to-day work. ATP is, in a sense, your only energy source, and it’s replenished by the food you take in daily, as well as the fuel stored in your body as fat or glycogen (the storage form of sugar). ATP is what’s converted into the energy you need to contract your muscles and perform all of your bodily functions. Using ATP for energy is analogous to burning coal in a furnace to run a steam engine. The burning coal heats the water that makes the steam that propels the engine.
At the peak of endurance training, athletes like Lance Armstrong require roughly 6,000 to 9,000 calories a day to keep their muscles working for extended periods of time. It seems like these elite endurance athletes must spend most of their nonexercise, nonsleeping time eating just to keep up with their training muscles’ demand for energy. For most of us, however, all the fuel we need for a regular exercise and weight loss program is easily consumed in the healthy meals and snacks we should be eating every day.
Another key point to understand about metabolism is that there are two types, and each one burns different fuels. Aerobic metabolism requires oxygen to make ATP and can use both sugar and fat as fuel. Anaerobic metabolism doesn’t use oxygen to make ATP and burns sugar and a compound known as creatine phosphate, which is made in the cells, for fuel.
If the words aerobic and anaerobic are familiar to you, it’s because we also use them to categorize different types of exercise. Aerobic activities (sometimes called cardio), which can be done for a long duration, include walking, cycling, rowing, and working out on a treadmill or an elliptical trainer. Since these are done at a relatively low intensity level, you can usually maintain your performance using the aerobic systems of the body. Therefore, by breathing more deeply and more frequently and having your heart beat faster, you can deliver sufficient blood and oxygen to supply your muscles’ needs without accumulating excessive waste products that can fatigue your muscles. Anaerobic activities, such as weight training, jumping rope, and sprinting, work muscles at a high intensity and consequently require energy faster than the aerobic systems can supply it, even though they’re working as hard as they can. The result is that your working muscles rapidly build up waste and tire out. Therefore, anaerobic exercise cannot be sustained for long, and you’re forced to reduce activity to a level where aerobic metabolism once more dominates.
There are several misconceptions about exercise in general and anaerobic exercise in particular. One of the biggest myths is that you can burn fat only by doing aerobic exercise. This idea is based on a misinterpretation of the fact that fat is an aerobic fuel, and it has led to a second, more insidious myth: When you work at a high-intensity anaerobic level, such as during interval training, you shut down your fat-burning machinery. This is simply not true; it’s based on a misconception about how your metabolism operates. We were once taught that the body can be in only one mode of metabolism at a time—either aerobic (burning suga
r and fat) or anaerobic (burning sugar and creatine phosphate).
In reality, as you exercise, your body slides freely between aerobic and anaerobic metabolism. Depending on the activity, your body may favor one type over the other, but it’s never exclusively in aerobic or anaerobic mode. You’re never actually burning just sugar, fat, or creatine phosphate. You’re burning all three fuels simultaneously. But, depending on your activity, you’re burning more of one than another.
When you do interval training, you’re repeatedly moving from high-intensity work to low-intensity work, and you’re also moving along the metabolic spectrum. You can’t maintain a high-intensity level for too long because you’ll get tired. Tiredness occurs for several reasons: First, you rapidly burn through your high-energy fuel, creatine phosphate, while you’re still burning sugar and fat. Second, your muscles make lactic acid and a number of waste products, which contribute to fatigue. So, to cope with this fatigue, you slow down and move into your low-intensity recovery period. During this recovery period, you’re not only burning off lactic acid as fuel, you’re also using fat and carbohydrates aerobically to replenish creatine phosphate and ATP. This allows you to do the next high-intensity spurt and continue to burn more fat and calories.
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FRINGE BENEFITS
Okay, you know that exercise can boost your metabolism and help you burn more fat and calories. But here are some other wonderful benefits you can get from working out.
Enhanced sex. If you want to get in the mood, get out your running shoes. Numerous studies have linked regular vigorous exercise with more frequent sexual encounters and enhanced sexual enjoyment for both sexes. A 2003 study of male health professionals found that men over age 50 who were physically active reduced their risk of erectile dysfunction by 30 percent. A study conducted at the University of British Columbia found that 20 minutes of intense exercise appeared to stimulate sexual response in women. About 15 minutes after the workout seemed to be the optimal time. Maybe couples should consider doing their workouts together!
Increased energy. Think you’re too tired to exercise? The problem could be that you need to get off the couch. Researchers at the University of Georgia analyzed 70 different studies on the impact of exercise on more than 6,800 subjects. The bottom line: Ninety percent of the studies reported that when sedentary people completed a regular exercise program, they experienced more energy and less fatigue, compared with people who did not exercise.
Better brainpower. Around age 40, the human brain begins to shrink, causing age-related changes in mental function, such as memory problems. Until recently, we believed that an aging brain couldn’t make new brain cells. We now know that it’s possible to make new brain cells well into old age, but there’s one catch: You have to work at it. Specifically, you have to do your cardio. A study of 60-to 79-year-olds conducted at the University of lllinois at Urbana-Champaign found that when people did 1 hour of aerobic exercise three times a week, their brains actually grew. More brain cells translate into better mental function—yet another reason it’s smart to exercise.
Longer life span. Exercise can add years to your life, according to a 2005 study published in the Archives of Internal Medicine. Researchers examined the medical records of more than 5,200 men and women who participated in the Framingham Heart Study, a groundbreaking study that has gathered information on diet, lifestyle, and health over a 40-year period and is still ongoing. People with even moderate levels of physical activity gained up to 1.5 years of life, and those who did more intense exercise lived, on average, 3.5 extra years. My belief is that not only did the more active people live longer, but they probably enjoyed a much better quality of life.
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The really exciting news is that with every additional interval, you burn an even higher proportion of fat. This is because with every subsequent interval, you require more and more oxygen for both the work and recovery portions. This means that you slide further and further toward the aerobic systems and use both fat and carbohydrates to rebuild the creatine phosphate and ATP needed for the next interval. However, you can still maintain higher levels of activity than would be possible during aerobic training at a constant pace, because the recovery periods allow replenishment of ATP and creatine phosphate and removal of waste products. The bottom line is that more energy is used, with more and more of it coming from the aerobic use of fat. And one last happy thought: The more you train, the more fat you burn during recovery.
As good as it is, intense interval training isn’t for everyone. It must be customized for people with certain orthopedic problems or serious heart conditions. Again, my advice is to check with your physician before starting this or any other exercise program.
And please, before you do any exercise, read the next chapter, “Boomeritis: The New Epidemic!” to make sure that you’re exercising safely.
5
Boomeritis: The New Epidemic!
From my discovery of baseball at the age of 5, I have always loved sports and have played just about all of them. Unfortunately, as I got older and spent more time in the office and at the hospital, pickup basketball, soft-ball, and touch football gradually faded into oblivion, except for occasional games with my two sons. My major athletic endeavor became tennis, which I played competitively in my youth and spent summers teaching. I also jogged on a regular basis (and had for years) and did short spurts of ice hockey (yes, ice hockey in Miami), karate, and Rollerblading. About 10 years ago, I gravitated to golf. I had to give up some of the more taxing sports because as I got older, I tended to get nagging injuries—particularly shoulder, low-back, and knee pain. I was not alone. Not surprisingly, the preponderance of such injuries among baby boomers like me has come to be known as boomeritis.
About 3 years ago, I began doing core training with Kris Belding, the Pilates teacher who designed the core functional fitness part of our exercise program, and I was amazed at how much better I felt. My overall strength and flexibility greatly improved, I felt younger, and I stopped experiencing the boomeritis aches, pains, and injuries that previously seemed to occur on a regular basis. And I finally fulfilled one of my mother’s longtime admonitions: “Stand up straight!”
While I was at home in Miami Beach, I had no trouble following my usual exercise and diet routine. But like so many people who travel a lot for business, I wasn’t always as diligent on the road and occasionally gained a few pounds during my travels. (I didn’t always follow my own advice about being prepared with healthy snacks.) Also, I found it difficult to put enough time into a cardio workout that was necessary to complement my core training.
Fortunately, about this time, I was lucky enough to meet my collaborator on this book, Joe Signorile, PhD, who teaches exercise physiology at the University of Miami. Joe told me about the benefits of interval training and convinced me that I could burn more calories and achieve a higher level of fitness in a shorter period of time than I was currently spending on my workout. While I had heard about interval training for competitive endurance athletes, I was unaware of its potential benefits for the rest of us. I reviewed the scientific literature he suggested and was convinced that interval training for nonathletes was an important advance.
The beauty of interval training—which, as I explained in the last chapter, involves doing short bursts of high-intensity exercise followed by an easier recovery period—is that you can do it wherever you are and adapt it to any activity.
As fate would have it, about the same time I met Joe, my friend and patient Mel was raving about his experience with boxing. I knew that Mel had boxed as a teenager, and I was surprised to hear that at age 72, he was back in the ring, albeit with a trainer. Mel’s wife, a former professional dancer, and I had been trying to get him to do regular exercise for years, but he was quickly bored by conventional workouts. I was delighted when I heard that he had kept up with his boxing lessons for more than a year—and it showed. His energy level had increased immensely and his blood chemistries
, blood pressure, and weight all reflected the benefits of his time in the ring.
Those of you who are unfamiliar with boxing may not know that it’s one of the most demanding of all sports. In fact, boxing is possibly the ultimate in interval training, with 2- to 3-minute rounds of intense exercise followed by a rest period.
I had always heard that boxers are among the fittest of all athletes and was curious to give boxing a try as a way to work intervals into my own cardio program. I was referred to a fabulous boxing trainer, Luis, and began working with him. But before I go further, let me put in an important disclaimer. What I did with Luis was baby boomer boxing: Luis held up hand pads and directed me on when and how to punch them. He was not allowed to punch me back!
What I learned was a progressive choreography, where my skills and fitness improved at a fast pace. Within a few months, I was “floating like a butterfly” around the ring. I was also clearly burning more calories in less time than during my previous long jogs or walks at a steady pace.
I was thrilled with my progress and improved fitness. But then I made a big mistake that led to injury, pain, and an unfortunate break from exercising. In fact, it’s what inspired me to write this chapter of warning for my fellow boomers.
At the end of our sessions in the ring, Luis and I would do some classic boxing exercises using a medicine ball. This was fine until I did a repetitive move of lifting, throwing, and catching the heavy ball over my head. Almost instantly, I felt a sharp pain in my left shoulder. But instead of stopping at that point, I disobeyed the advice I always give to my own patients: I ignored the pain and continued with the over-the-head exercise. Over the next few days, the pain in my shoulder got worse.
The South Beach Diet Super Charged Page 6
