Ingesting sugar during exercise is a very good thing, says a new a study from Denmark. The benefits are increased power and endurance as well as the amount of training that can be done.
Cycling advocate Gabe Mirkin, M.D. reports on the study in his e-zine, citing the June 2009 issue of the Journal of Applied Physiology. Note that the doctor uses the terms "sugar" and "carbohydrate" interchangeably.
As Dr. Mirkin tells it, the Danish researchers had men exercise with one leg while drinking a 6% sugar solution and the other leg while taking an artificially sweetened (sugarless) drink. They worked out 2 hours a day on alternate days, 5 days a week. The legs trained with sugar had 14% more power and a 30% greater
time to exhaustion.
"Running out of muscle sugar makes you feel tired," Dr. Mirkin explains. "So anything that preserves stored sugar in muscles during a workout will help you exercise longer.
"This study shows that taking sugar regularly during workouts allows you to extend the amount of training without lessening the benefits that you receive from the extra work."
In a related issue, the researchers looked into whether restricting carbohydrate during training could enhance performance by teaching muscles to get by with fewer carbs.
"These authors showed that the enzymes used to convert sugar and fat to energy function just as well when sugar is taken continuously during exercise," Dr. Mirkin reports. "The muscles trained on sugar had no loss in the amount of stored sugar or the ability to convert food to energy."
Protein Too
Another study (International Journal of Sport Nutrition and Exercise Metabolism, April 2009) cited by Dr. Mirkin has shown that using a drink containing protein (1.8% solution) as well as sugar (6% solution) every 3 miles and at the finish of a 36-mile bicycle time trial was more effective than a drink containing just sugar in 2 ways:
it helped the cyclists ride faster near the end of the time trial
it lessened next-day muscle soreness
Also, drinking 500 ml (2 cups) of the protein-sugar beverage immediately after intense exercise hastened healing of muscle damage (Journal of Applied Physiology, April 2009).
Dr. Mirkin notes that ingesting refined carbohydrate (sugar or flour) when not exercising can cause a rise in blood sugar that increases risk for diabetes and heart attack. But he says that contracting muscles remove sugar so fast from the bloodstream that blood sugar usually does not rise too high during exercise and for up to 30 minutes afterwards.
(RBR keeps an eye on Dr. Mirkin's reports because they frequently have information that pertains to cyclists. He's a roadie who at age 75 averages 200 miles [322 km] per week. You can subscribe to his free e-zine on his website at
[URL]http://www.drmirkin.com[/URL])