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Research Suggests Link Between Muscle Soreness and Poor Glucose Tolerance
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by Dr. Lonnie Lowery
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Glucose intolerance is the body’s inability to get blood glucose (from dietary carbohydrates) into the tissues. Skeletal muscle is a primary target for this glucose disposal. In fact, muscles need the glucose in order to recover from exercise. Consequently, much research on runners, cyclists and team sport athletes suggest the need for high carbohydrate diets. But are bodybuilders like endurance athletes? Many athletes know that eccentric exercise ("negatives") induce superior muscle growth but recovery periods are long. Does this type of intense training alter dietary needs? What happens when muscle tissue is "traumatized" and sore from intense weight training? Some almost disturbing answers are coming from the new Human Nutrition Laboratory (HNL) at Kent State University.
Lonnie Lowery, a professor there who also directs research in the HNL, recently submitted data with student, Traci Sexton to the prestigious Ohio Academy of Sciences annual meeting (March 2001). The presentation there will reveal the significant relationships among muscle damage variables like muscle soreness, serum creatine kinase and glucose tolerance.
Preliminary data from the first in a series of studies on muscle recovery suggests that the popularity of lower-carb diets among intense lifters may be justified. Twenty-four hours after a bout of bench pressing and squatting (six sets of six "negatives" at 80% of their one-rep max), subjects presented statistically significant soreness and elevated serum enzymes. Despite the necessarily tight control of blood glucose in the body, an oral glucose tolerance test (OGTT) has revealed elevated blood glucose concentrations in all subjects to date. Although this particular variable in the study is as yet non-significant, statistical power calculations suggest that it’s significance will be realized by the end of the protocol. "We didn’t expect to see actual blood glucose aberrations from the exercise bout," says Lowery. "The hypothesis was that subjects’ pancreases would have to secrete more insulin to deal with the muscle micro-trauma." Theoretically, too much circulating insulin bodes poorly for body fat accumulation but appears to be necessary to deal with eccentric exercise-induced glucose intolerance. Insulin results will comprise part of a follow-up study by Lowery, Mendel and Ziegenfuss. Relative hyperinsulinemia has been shown in the past with lower body eccentric exercise.
Despite insistence to the contrary from many dietitians and exercise physiologists, athletes who train to the point of muscular soreness feel strongly that "carbs make them fat." Data from the Human Nutrition Laboratory at Kent (partly funded by pharmaceutical conglomerate, Phoenix Labs) appears to be providing some support for this notion. If sore muscles aren’t taking-up the carbohydrate very well, the body will store it in other tissues. This simultaneously retards muscle recovery and may, indeed induce lipogenesis in adipose tissue (build body fat). The term, "population specificity" designates that research results only apply to those people similar to the research subjects. For bodybuilders, reliance upon sport nutrition recommendations that stem from endurance athletes may be a mistake. Perhaps this new series of studies will tone-down or modify the "high carbs for everyone" recommendations that pervade sports nutrition.
--------------------------------------------------------------------------------
by Dr. Lonnie Lowery
--------------------------------------------------------------------------------
Glucose intolerance is the body’s inability to get blood glucose (from dietary carbohydrates) into the tissues. Skeletal muscle is a primary target for this glucose disposal. In fact, muscles need the glucose in order to recover from exercise. Consequently, much research on runners, cyclists and team sport athletes suggest the need for high carbohydrate diets. But are bodybuilders like endurance athletes? Many athletes know that eccentric exercise ("negatives") induce superior muscle growth but recovery periods are long. Does this type of intense training alter dietary needs? What happens when muscle tissue is "traumatized" and sore from intense weight training? Some almost disturbing answers are coming from the new Human Nutrition Laboratory (HNL) at Kent State University.
Lonnie Lowery, a professor there who also directs research in the HNL, recently submitted data with student, Traci Sexton to the prestigious Ohio Academy of Sciences annual meeting (March 2001). The presentation there will reveal the significant relationships among muscle damage variables like muscle soreness, serum creatine kinase and glucose tolerance.
Preliminary data from the first in a series of studies on muscle recovery suggests that the popularity of lower-carb diets among intense lifters may be justified. Twenty-four hours after a bout of bench pressing and squatting (six sets of six "negatives" at 80% of their one-rep max), subjects presented statistically significant soreness and elevated serum enzymes. Despite the necessarily tight control of blood glucose in the body, an oral glucose tolerance test (OGTT) has revealed elevated blood glucose concentrations in all subjects to date. Although this particular variable in the study is as yet non-significant, statistical power calculations suggest that it’s significance will be realized by the end of the protocol. "We didn’t expect to see actual blood glucose aberrations from the exercise bout," says Lowery. "The hypothesis was that subjects’ pancreases would have to secrete more insulin to deal with the muscle micro-trauma." Theoretically, too much circulating insulin bodes poorly for body fat accumulation but appears to be necessary to deal with eccentric exercise-induced glucose intolerance. Insulin results will comprise part of a follow-up study by Lowery, Mendel and Ziegenfuss. Relative hyperinsulinemia has been shown in the past with lower body eccentric exercise.
Despite insistence to the contrary from many dietitians and exercise physiologists, athletes who train to the point of muscular soreness feel strongly that "carbs make them fat." Data from the Human Nutrition Laboratory at Kent (partly funded by pharmaceutical conglomerate, Phoenix Labs) appears to be providing some support for this notion. If sore muscles aren’t taking-up the carbohydrate very well, the body will store it in other tissues. This simultaneously retards muscle recovery and may, indeed induce lipogenesis in adipose tissue (build body fat). The term, "population specificity" designates that research results only apply to those people similar to the research subjects. For bodybuilders, reliance upon sport nutrition recommendations that stem from endurance athletes may be a mistake. Perhaps this new series of studies will tone-down or modify the "high carbs for everyone" recommendations that pervade sports nutrition.
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