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Sugar Helps You Exercise Longer

Bicycle racers in long events such as the Tour de France take sugar supplements while they ride to increase their endurance. If you plan to exercise for more than two hours, you can help yourself last longer by taking a source of sugar after 30 minutes and several times more throughout your event.

When you exercise, you convert food to energy for your muscles by stripping off electrons and hydrogen from the foodstuffs. This process manufactures a chemical called ATP that provides energy that does not require oxygen. A study from the University of Waterloo in Ontario, Canada shows that taking sugar during prolonged exercise raises levels of ATP (American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, July 2007). At exhaustion, ATP levels were at the same low levels in both the group taking sugar and those taking artificial sweeteners. However, prior to exhaustion, those taking sugar had higher levels to help them exercise longer.

You do not get this benefit from sugar eaten before you exercise because high blood sugar levels that result will cause your pancreas to release large amounts of insulin. The extra insulin will deplete the sugar stored in your muscles faster and tire you earlier. Thus if you want to exercise intensely for more than a couple of hours, you need to eat or drink a source of carbohydrates at frequent intervals during your activity.


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Dear Dr. Mirkin: How much walking do I need to do to lose weight?

For exercise to help you control weight, you must exercise fairly intensely or else you need to exercise for many hours, and most people do not have the time to exercise for three or four hours or more every day. A study from the University of Massachusetts in Boston shows that middle-aged women who exercise at very low intensity are fatter and gain weight far more easily than women who exercise more intensely (American Journal of Health Promotion, July-August 2007).

This is what you would expect. When you exercise intensely enough to raise a sweat, you can increase your metabolism and continue to burn extra calories for several hours after you stop exercising. When you exercise at very low intensity, you do not increase your metabolism and you have to exercise for a very long time to burn a significant number of calories. If walking is your exercise choice for weight loss, walk vigorously enough to sweat and breathe hard.

People who want to use exercise to control weight should first check with their doctors. They should pick an activity that they can do regularly and try to do it every day. On some days, they should try to exercise more intensely, feel sore on the next day, go at low intensity for as many day as it takes for the soreness to go away and then exercise intensely again. People are more likely to stick with an exercise program if they do it with a spouse, a good friend or a personal trainer, or in a social setting such as a class or club.


Dear Dr. Mirkin: Does fluoride prevent cavities by killing bacteria in the mouth?

Fluoride has some antibacterial action, but that is not its primary value for your teeth. Drinking fluoridated water or brushing teeth with a toothpaste that contains extremely small amounts of fluoride helps to strengthen your teeth.

Teeth constantly release minerals and then take in new minerals. You need only very small amounts of fluoride in your saliva all the time to increase the rate that minerals enter teeth. Fluoride causes calcium phosphate crystals to form, which in turn forms hard fluorhydroxyapatite in teeth to make them stronger. The amount of fluoride that stays in saliva from your toothpaste or drinking water so minute that it is unlikely to change the bacterial content of your mouth, but it is sufficient to help keep your teeth strong.


Recipe of the Week

Turkish Three-Bean Soup

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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