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Muscle Sugar: Train Low and Compete High

Muscles use carbohydrates, fats and proteins for energy. You can improve both endurance and speed in athletic competitions lasting more than a couple hours by training your muscles to burn more sugar and less protein and fat during competition.

The most efficient fuel for muscles during exercise is carbohydrates (sugar). The limiting factor for how fast you can move is the time it takes to move oxygen into muscles. Since sugar requires less oxygen than protein or fat, you move faster when your muscles burn primarily sugar. How far you can run, cycle, ski, or skate depends on how much sugar you can store in your muscles before you start exercising and how long you can keep the extra sugar there. When muscles run out of their stored sugar, muscles hurt and you feel tired.

Advantages of Training on Depleted Glycogen
You can teach your muscles to burn more sugar and less fat by starting some of your workouts with muscles that are low in their stored sugar, called glycogen. This forces muscles to burn a higher percentage of fat. However, muscles move faster when they use sugar for fuel, so they try to burn more sugar. They increase the concentration of the many enzymes that help to convert sugar to energy. This allows muscles to burn a higher percentage of sugar during competition so athletes can go faster and improve their chances of winning.

Ways to Deplete Muscle Glycogen
You can start your workouts with low muscle glycogen by: *training after skipping breakfast; *training twice a day, so your muscles have low stored sugar during your second workout of the day; *restricting carbohydrates in your diet during training; *taking prolonged workouts that empty your muscles of stored sugar, or *withholding carbohydrates after a hard workout. The key is to train with low amounts of stored muscle sugar and race with muscles full of stored sugar (Exercise and Sports Science Reviews, October 2010).

How to Increase Sugar-burning Enzymes in Muscles
You can't start all your training workouts with low muscle sugar because it will slow you down, reduce the amount of miles you can do in training, and increase your chances of injuring yourself.

Knowledgeable athletes train by stressing and recovering. They take a hard workout on one day, feel sore on the next, and then take easier workouts until the soreness disappears. They do very intense workouts up to three times a week, rarely on consecutive days. These intense workouts should be taken with muscles full of sugar, so you should eat before your intense workouts and even take sugar during the workout.

However, on your four recovery days, try starting your workouts without eating breakfast. If you feel excess fatigue, your muscles hurt or you have little energy, shorten your workouts and immediately eat extra carbohydrates such as fruits, vegetables, whole grains, beans, and even whole grain bread or pasta.

If you find that you are fatigued too often and take too long to recover from workouts, abandon this training technique. It is not for you. You probably have to take in a lot of sugar during training just to keep up the intensity and volume of work that is required to be a competitive athlete.

What to Do Before Competition
Hundreds of research papers show that you can increase endurance and intensity in competition by filling your muscles with sugar before you compete and then taking sugar during competition. Athletes in endurance events should cut back on their training three days before major competitions and eat extra carbohydrates. This fills their muscles with extra sugar. They should eat a high-carbohydrate breakfast and take sugar during the competition to keep up a regular sugar supply for their muscles.


Breakthrough for Irritable Bowel Syndrome

A report in the New England Journal of Medicine shows that rifaximin, a poorly absorbed antibiotic, relieves the alternating constipation and diarrhea that causes cramping and abdominal pain in Irritable Bowel Syndrome (NEJM, January 6, 2011).

For the last 40 years I have been helping patients with irritable bowel syndrome by prescribing an antibiotic called metronidazole, and for the last 40 years my colleagues have criticized me for doing this. Take a look at some of the articles I wrote many years ago:

On the basis of the report in the New England Journal of Medicine, people who have intestinal symptoms and all tests that the doctor orders cannot find a cause, it would be reasonable to take an antibiotic for a week or more.


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Follow-up on Exercising on an Empty Stomach to Prevent and Treat Diabetes
I received many questions on this report. Here is a more detailed explanation:

Most cases of diabetes are caused by inability to respond to insulin (type II diabetes). This can be cured and prevented by exercising (Medicine & Science in Sports & Exercise, December 2010), and this benefit is enhanced if you exercise after an overnight fast ((Exercise and Sports Science Reviews, October 2010).

Before insulin can do its job of driving sugar into cells, it must first attach to special hooks on each cell, called insulin receptors. Anything that prevents insulin from attaching to its receptors on cells can cause diabetes.

Having too much fat in a cell blocks insulin receptors, so anything that causes fat to accumulate inside cells blocks insulin receptors. When you eat; *blood sugar levels rise, *your pancreas releases insulin to drive sugar into cells, *sugar enters muscle cells, *sugar is burned for fuel or stored as glycogen (stored muscle sugar). *When glycogen stores are full, *all additional sugar is converted to fat to block insulin receptors even more, *to cause metabolic syndrome and diabetes.

Therefore, both prevention and treatment of diabetes call for emptying fat out of fat and muscle cells. Resting muscles require insulin to drive sugar into their cells. Contracting muscles can draw sugar into their cells without insulin (Journal of Applied Physiology, December 2003).

Muscle cells can use carbohydrates, fats and protein for energy. The most efficient fuel for muscles during exercise is carbohydrates (sugar). Emptying muscles of glycogen increases their use of fat for energy. After a 12-hour fast, muscle sugar (glycogen) is low. Exercise in the morning before you have breakfast. This depletes your already reduced stores of glycogen, which, in turn, forces you to use up stored muscle fat for energy. Reducing fat stored in muscles increases a muscles ability to respond to insulin. This can help to prevent and treat diabetes.

However once you have diabetes, you are at increased risk for heart attacks. We do not know if exercising after fasting can harm diabetics with heart disease, but diabetics should check with their doctors before changing any exercise program.


Recipe of the Week:

Sweet Potato Salad with Pineapple

You'll find lots of recipes and helpful tips in The Good Food Book - it's FREE

January 9th, 2011
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About the Author: Gabe Mirkin, MD

Sports medicine doctor, fitness guru and long-time radio host Gabe Mirkin, M.D., brings you news and tips for your healthful lifestyle. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology. The Dr. Mirkin Show, his call-in show on fitness and health, was syndicated in more than 120 cities. Read More
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