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Longer Lower Legs More Efficient

People who have longer lower leg lengths (the distance from knee to ankle) will usually have greater endurance during running or walking than those with shorter lower leg lengths. Researchers at the University of Wisconsin showed that people with longer lower legs use less energy when they run (Journal of Human Evolution, August 2007).

In a previous paper in the same journal, these authors showed that people with longer lower legs are better able to prevent heat build-up, which slows you down and makes you tired. When you exercise, almost 80 percent of the energy that you use to power your muscles is lost as heat. So the harder you exercise, the more heat you produce and the harder your heart has to work to get rid of the extra heat. You prevent heat buildup by your heart pumping hot blood from your muscles to the skin where it is cooled by sweat and conduction and radiation.

People with longer lower limbs use up less oxygen and produce less carbon dioxide for the same energy expenditure. Therefore they are more efficient and can go further because their bodies require less oxygen.


Reports from

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Dear Dr. Mirkin: I'm trying to lose weight; do I need to avoid all foods that cause a high rise in blood sugar?

How foods affect blood-sugar levels varies from person to person and from one time to another in a single individual. For example, if you eat a jelly donut in the evening, your blood sugar may rise well over 200 (it should never be higher than 160). If you eat the jelly donut while you have been riding your bike for more than an hour, your blood sugar level may not rise at all.

Researchers at University Medical Center in Utrecht, the Netherlands showed that eating sugar and flour markedly increases risk for heart attacks in middle-aged women. Being overweight increased the risk even more (Journal of the American College of Cardiology, July 2007). More than 15,000 healthy Dutch women, ages 49-70, were followed for nine years. They suffered 556 cases of coronary heart disease and 243 strokes. The ones most likely to be afflicted were overweight women who ate a diet high in foods that cause a high rise in blood sugar.

The only places that you can store sugar in your body are your liver and muscles. If you eat lots of sugar or flour when your muscles are full of sugar, sugar goes from your intestines, into your bloodstream and then can spike to high levels. However, during or after prolonged exercise, sugar goes from your intestines into your bloodstream and then directly into your muscles, so it does not spike. For diabetics or overweight people, the safest time to eat foods that cause a high rise in blood sugar is while they are exercising.


Dear Dr. Mirkin: Does coffee improve memory?

Caffeine may protect against loss of memory or thinking skills in older women, according to a study published in Neurology (August 7, 2007). The researchers studied cognitive decline, dementia and caffeine intake of 4,197 women and 2,820 men aged 65 and over in three French cities for four years. They tested the participants' cognitive skills at the start of the study and again at years two and four.

The results showed that compared to women who drank only one cup a day or less, women who drank three or more cups of coffee or tea a day had a 33 per cent reduced risk of decline in verbal retrieval over the four years. The protective effect of caffeine appeared to increase with age, rising from a 27 per cent reduced risk for women aged 65 to 74, to 70 per cent for women aged 80 and over. No link between caffeine and cognitive decline was found in men, nor was caffeine consumption found to affect the incidence of dementia over the four years of the study. Before you increase your coffee intake, note that other studies suggest that caffeine can raise blood sugar and blood pressure. The question of benefits or harm from caffeine is far from settled.


Thanks to everyone who recommended more healthful restaurant choices.
Here's the updated list


Recipe of the Week

Mediterranean Seafood Stew

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

June 26th, 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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