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Carbohydrate Snacks for Endurance

If you have a physically demanding job that keeps you moving all day, you may have greater endurance if you eat small snacks throughout the day instead of having a single large meal at lunchtime. Researchers at the University of Montana in Missoula showed that snacking on carbohydrates may prolong your endurance during a long day of continuous movement (Medicine & Science in Sports & Exercise, December 2007). They asked men and women to exercise intermittently for ten hours. Each hour, they performed nine minutes of upper-body weight lifting, 19 minutes of cycling, and 20 minutes of walking on a treadmill, with a 1-minute rest between each exercise. This was followed by a 10-minute rest and feeding period. Those who took carbohydrates every hour were able to keep more sugar (glycogen) in their muscles, and were able to exercise longer without feeling tired.

When you exercise, your muscles get their energy from muscle sugar and fat stored in muscles, sugar and fat from the bloodstream, and to a lesser degree from protein. When your muscles run out of their stored sugar, they require more oxygen to burn food for energy. This can make your muscles feel tired and be more difficult to coordinate. Eating any source of sugar or carbohydrates during exercise preserves muscle sugar and increases endurance.


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Dear Dr. Mirkin: Should older people take growth hormone to preserve muscle size and strength?

As you age, expect to lose muscle fibers and strength unless you exercise. A study from the University of Florida in Gainesville shows that a program of exercise training later in life helps aging rats to reverse this age-related loss of muscle size and strength (American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, November 14, 2007). The study also showed that short-term administration of growth hormone late in life does not prevent loss of muscle strength. Previous studies show that it may help people get rid of fat.

At this time, there is not enough evidence for an older person to take growth hormone to improve muscle strength, and there is no long-term data on safety. Sudden deaths reported in athletes who have taken growth hormone are probably due to the effect of enlarging the heart muscle without also adequately enlarging the blood supply. The larger heart requires more blood and cannot meet its needs for oxygen, so it starts to beat irregularly.


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Dear Dr. Mirkin: Do you recommend the HPV vaccine?

The human papilloma wart virus (HPV) causes cervical and penile cancers as well as some cancers of the mouth. Once people are infected with HPV, they keep the virus forever and cannot be cured. The new quadrivalent HPV vaccine prevents infections with this virus only if it is given before a person is infected.

There are more than 60 wart viruses, but four cause the vast majority of cancers (types 6,11,16, & 18). A quadrivalent vaccine that contains all four of these types has been shown to be almost completely effective in preventing cervical and genital disease related to these viruses in 16 to 26-year-old women who have not already been infected with these viruses.

A new study shows that giving the vaccine to women who are already infected with one or more of these viruses prevents cervical cancer caused by the remaining types (Journal of Infectious Diseases, November 2007). These results support vaccination of the general population without prescreening. Young women should be given the vaccine before they become sexually active, so most doctors recommend vaccination of nine- year-old girls.


Recipes for your holiday buffet

Salmon Mousse
Artichoke-Wild Rice Salad

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

June 25th, 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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