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Exercising on an Empty Stomach Can Both Prevent and Treat Diabetes

One of three North Americans will become diabetic because they eat a high-calorie, high-fat diet that *blocks insulin receptors *to prevent cells from responding to insulin (insulin resistance) *to cause high insulin levels *that constrict coronary arteries *to cause heart attacks. Failure to respond to insulin causes *high blood sugar levels *that cause sugar to stick to cell membranes *to permanently damage the affected cell *to cause blindness, deafness, heart attacks, strokes, amputations and all the terrible side effects of diabetes.

After just a few days on a high-calorie, high-fat diet, cells fail to respond adequately to insulin, blood sugar levels rise, fat deposits in your body, even in muscles, and you gain weight. This causes your muscles to start to lose their ability to store glycogen, the major source of efficient fuel for exercise, and you tire much earlier during exercise.

If you exercise vigorously BEFORE breakfast, you can reduce and even prevent these side effects. Exercising after fasting prevents fat from being deposited in muscles and helps muscles to make more stored sugar (glycogen), the primary efficient fuel for exercise. A study from Leuven, Belgium shows for the first time that "fasted training is more potent than fed training to facilitate adaptations in muscles, and to improve whole-body glucose tolerance and insulin sensitivity" (Journal of Physiology, November 2010). So you are able to exercise longer and harder. If you do not exercise during this period, you gain none of these benefits. If you exercise after eating, these benefits are reduced markedly (Journal of Physiology, April 15, 2005).

When you exercise after fasting, you burn primarily your own body fat for energy. The fat is removed from fat cells and muscle cells. Muscle enzymes burn fat more efficiently and clear further fat from your muscles and fat cells to make your cells more sensitive to insulin. This reverses the cascade described in the first paragraph.

However, fasting before exercising harms training and competitive performance in athletes. The limiting factor to how fast you can move your muscles is the time it takes to move oxygen into muscles. When you fast before exercising, you burn more fat and less sugar. Since sugar requires less oxygen than fat to be converted to energy, your needs for oxygen are greater to burn fat. This slows you down and tires you earlier.

The basic research that showed how muscles convert sugar to energy was done in the 1930s by Diana's father, professor Donald Purdie of Cambridge University in England. He worked with Hans Adolph Krebs, who won the Nobel Prize for Physiology or Medicine in 1953.

It is not established whether athletes should train on a low carbohydrate diet to teach their muscles to burn sugar more efficiently. This would help them to compete at a faster pace. Several studies show that training after fasting increases enzymes that turn sugar into energy. However, training with reduced sugar stores (glycogen) can limit workouts, and this may counteract the gains of fasting before working out.

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Dear Dr. Mirkin: What can I do about painfully cold fingers?

If your fingers turn white and start to hurt when you're out in the cold, you may have a condition called Raynaud's phenomenon. On exposing your fingers to cold, the blood vessels close, skin turns white and their temperature drops. When skin temperature reaches 59 degrees F, your brain tries to save your skin by opening the blood vessels, and the skin turns red and starts to itch and burn. If you warm your hands at this point, your skin will not be damaged, but if you do not get out of the cold, the blood vessels in your hands can close and the temperature in your hands can drop to freezing, resulting in frostbite. Several diseases, smoking, or using vibrating equipment can cause Raynaud's phenomenon.

If your fingers start to feel cold, swing your arms rapidly from the shoulders, with a straight elbow. This will drive blood, like a centrifuge, into the fingers to warm them. Wear two or more layers of gloves or mittens. Single-use hand warmer packets can keep you from being miserable when you want to stay outside. They are available in sporting goods stores or online.

Blood pressure drugs called calcium channel blockers (Nifidipine) can help to treat and prevent Raynaud's phenomenon. Another option is nitroglycerin ointment, a prescription medication that is used to treat heart pain. When applied to the forearm, it opens blood vessels leading to the hands.

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Follow-up on finger length and testosterone:

Having a ring finger that is longer than your index finger is associated with greater athletic ability in men (American Journal of Human Biology, Mar-April 2009) and in women (British Journal of Sports Medicine, December 2006). The longer your ring finger is compared to your index finger, the better athlete you usually are (Strength Conditioning Research, published online August 20, 2010).

The ratio of the ring finger to the index finger is determined by how high your testosterone levels were in the uterus before you were born. Testosterone stimulates bone growth. Men exposed to higher levels of testosterone in the uterus also tend to have higher levels of testosterone later on.

On the average, men tend to have longer ring fingers, and women tend to have longer index fingers. The higher the testosterone in utero, the greater the length of the ring finger and the more "masculine" the resulting child - whether male or female. The difference between men and women in digit lengths usually is greater on the right hand.

In men, a longer ring finger is also associated with increased risk for prostate cancer; see the 12/5/10 eZine

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Recipe of the Week:

A delightful new holiday recipe from one of our readers:

Kaarin's Christmas Cranberry Curry

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

June 21st, 2013
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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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