"When you exercise continuously for more than about 10 minutes, your heart adapts by becoming more efficient. It achieves this efficiency through downsizing. Long-duration exercise makes the heart, lungs, and muscles smaller so that they can go longer with less energy, but there's a trade-off. The cardiovascular system becomes very good at handling a 60minute jog, but it gives up the ability to provide you with big bursts of energy for short periods. Far from protecting your heart, this loss makes you more vulnerable to a heart attack. . .
"Heart attacks don't happen due to a lack of endurance. They typically come about when a person is either at rest or when there's a sudden, sizable demand on the heart. Heart attacks often strike when someone lifts a heavy object, has sex, or experiences an unexpected emotional blow. For one reason or another, the oxygen supply to the heart can't keep up with a change in demand.
"Studies have demonstrated that short-duration exercise improves cardiovascular health more than long-duration exercise. A recent Harvard study found that men who performed shorter bouts of exercise reduced their heart disease risk by 20 percent. (Access the studies at the end of each chapter in Dr. Sear's book.)
"Dr. Stephen Seiler recently compared 20 minutes of running on a treadmill to running for 2 minutes followed by 2 minutes of rest for five cycles. He reported at the American College of Sports Medicine that interval exercise improved maximal cardiac outputs while continouse exercise did not. Intervals also produced another important improvement not seen with continouse exercise, the development of quicker cardiac adjustments to changes in demand. The interval trainees also achieved "higher peak stroke volumes." . . . that is the highest volume of blood your heart can pump per beat when challenged.
"Interval training also lowers cholesterol levels. . .it can improve your cholesterol ratios. Reserachers studied middle-aged, sedentary men and women who performed ten-minute bouts of exercise throughout the day for six weeks. The blood tests of the men and women showed both a drop in total cholesterol and a rise in beneficial HDScholesterol.
"Interval training also helps exercisers maintain healthy testosterone levels. Testosterone levels increase more in men who do interval exercise than in those doing endurance training. . . more youthful testosterone levels help older men maintain their muscle mass, libido, and bone integrity. (Marcia adds that normal testosterone levels would help prevent hair loss.)
"Every year very well-conditioned long-distance runners suffer sudden cardiac death. Distance runners have higher rates of sudden cardiac death than other athletes do. Modern marathons have emergency stations specifically equipped to handle the abnormal heart rhythms, heart attacks, and other cardiac emergencies that can be expected to occur. This increased risk appears regardless of culture or diet.
". . .a report in the American Journal of Cardiology found that distance running disrupted the balance of blood thinners and thickeners, elevating clotting levels and inflammatory factors. These changes are signs of heart distress, not a heart that's becoming stronger after exercise.
"The bottom line is that to use your willpower to force yourself into frequently repeating continous 'cardio' is not mimicking the natural condition. In nature, our path, pace, stride, intensity, positioning, and force during exercise all occur in starts and stops to meet the changing demands of our surroundings. Your body is designed to work in interval bursts.
Shed More Fat with Interval Exercise
Most people think that the longer they work out, the more weight they will lose. They plod on mile after sweaty mile, assuming that they are melting off unwanted fat with every step. In fact, these dedicated but misinformed exercisers are undermining their own efforts! Endurance exercise is not the best way to lose body fat. Long-term exercise calls on the body to store more fat!
I'm summarizing now: You do burn a great amount of fat by long, moderate-intensity exercise, but only during the 30-60 minutes you are working out. It's what occurs after you stop exercising that actually adds more fat to your body.
"Your body is always adapting to the demands put on it. When you burn fat during exercise, you are telling your body to maintain fat stores so that they will be available for the next exercise session. In essence, your body hoards your fat reserves to use as fuel for future workouts. Instead of decreasing fat, this type of endurance exercise triggers your body to make more fat whenever possible. You get the highest percentage of your energy needs from fat while you are at rest.
"Endurance exercise actually encourages fat production. When you begin working out, your body burns ATP, the highest energy fuel in the body, but there is only enough ATP for one or two minutes of exercise. Next, your body switches to glycogen, a carbohydrate stored in muscle tissue. Your glycogen stores will take you through about 15 minutes of exercise. After that, your body taps into its fat reserves for fuel. . . since your body does all it can to adapt to demands, it builds back your fat the next time you eat to prepare you for the next time you exercise for a long time. It also sacrifices other tissues, such as muscle, to preserve fat whenever possible.
"One of the primary reasons people choose the wrong form of exercise is that they presume that their body changes during an exercise session. It never does. All the important changes begin after you stop working out. They are consequences of your body adapting to prepare for the next time you ask your body to perform that same activity.
"A number of studies also confirm the phenomenon. For example, reasearchers at Colorado State University measured how long our bodies continue to burn fat after brief periods of exercise. Study participants exercised for 20 minutes in sets of two-minute intervals of exercise, and one-minute rest periods. The reserachers found that participants still burned fat 16 hours after the interval exercising! At rest, their fat oxidation was up by 62 percent, and their resting metabolic rate rose 4 percent. In other words, interval exercise continues to trigger fat burning long after the session is over."
Dr. Sears goes on to cite other interesting studies supporting the need for interval exercising. He also explains the need for exercises that build muscle mass. He has a program for interval exercising one day and muscle mass building the next. It is all simple and not time-consuming.
I recommend that you get the T-Tapp program. I did parts of it when we lived in Guatemala then gave it up for a daily 40-minute workout on the treadmill. Today I went back to T-Tapp recognizing that it is exactly what Dr. Sears is advocating: interval training. I also will continue with 20 minutes on the treadmill but will do it in intervals.
Dr. Sears also dedicates a few chapters in his book to the necessity of eating more protein in order to lose weight. He says, "When you eat protein, your body produces growth hormones that build muscles. When you eat carbohydrates, your body secretes insulin to digest carbohydrates and build fat." He talks a lot about low-carb eating and explains how carbs cause a spike in blood sugar. Too much glucose in the blood is converted to fat not energy. My sister-in-law gave me a couple of references for low-carb eating: The Idiot's Complete Guide to Low-Carb Meals. You can find more online. This sister-in-law lost 30 lbs, about a pound a week learning to eat low-carb. I don't have a lot to lose, about 5 lbs, but I have had to fight like crazy to not gain. I now understand why; I was exercising too much causing my body to store the fat. It also made me too hungry.
I hope this has been helpful information. Please weigh in with any insights you may have. I now understand why several of my relatives and friends who have tremendous will-power could not lose weight in spite of several hours of exercise a day. It just didn't make sense until I came across this book how anyone could work out so long and hard and still not drop a pound. These latest studies shed light on it.
I am all for interval workouts and their benefits. However, please explain to me how hard core cross country runners have such low percentages of body fat and are so dang skinny if their type or exercise actually encourages fat production and storage.
ReplyDeleteI've wondered that, too. I guess it's true for those of us who are puffing away for 30-60 minutes and in spite of our healthy eating we don't drop a pound. Most of us aren't marathon runners. Maybe there is just no way you can store fat when you are running several hours a day.
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