Protein, Weight Lifting, Preservation of Muscle Mass, and Sarcopenia

Posted by on Dec 9, 2014 in Research Highlights and Insights

A look at a recent publication: Dickinson JM et. Leucine-Enriched Amino Acid Ingestion after Resistance Exercise Prolongs Myofibrillar Protein Synthesis and Amino Acid Transporter Expression in Older Men. J. Nutr. 144:1694-1702,2014 Aging is associated with a gradual and involuntary loss of skeletal muscle mass in both men and women, which leads at some point to a decline in muscle strength and function. Age -elated loss of muscle mass and function is known as sarcopenia. On average, we loose about 1% of our muscle each year, beginning around age 30. Although there is some variability in the rate of sarcopenia, decline in muscle mass is pretty much inevitable. Sarcopenia Sarcopenia is a major contributor to loss of mobility, frailty, and independent living as we “mature.” Skeletal muscle is responsible for about 75% of our body’s control of blood sugar, and elevated blood sugar is a major risk factor for accelerated aging and premature death, primarily due to cardiovascular disease (preserving muscle mass as we age is a major longevity enhancing strategy. (NOTHING good happens to our body as fasting blood sugar rises.) Resistance Exercise (RE) It is estimated that there will be approximately 71 million Americans 65 and older by 2030, and sarcopenia will play a major role in rising health care costs, along with many people not having a “healthspan” anywhere near their lifespan. Resistance exercise (RE) or weight lifting is the primary strategy to enhance and preserve muscle mass and strength at ALL ages. Tips for maximum strength creation, preservation, and muscle endurance: Number of sets per exercise: one set Speed of movement: slow, non-explosive Number of repetitions: 8 to 12 with maximum 20 reps ** Frequency of training: twice per week for most muscle groups **from Smith D and Bruce-Low S. Strength Training Methods and the Work of Arthur Jones. Journal of Exercise Physiology online. 2004;7(6): 52-68 A review of the published literature seems to indicate that varying the number of repetitions, higher or lower, does not produce differing effects on strength or muscular endurance. The exercises should be done to the point where it is hard to do more without help. Additional material on Resistance Exercise: cdc.gov/physical activity/everyone/guidelines, and NutritionAction.com/ExerciseReport Protein Ingestion Post RE In ALL age groups essential amino acids have the ability to stimulate muscle protein synthesis, however, relative to younger individuals, older adults have an impaired muscle protein synthesis response to RE. In ALL age groups the essential amino acid Leucine helps drive the production of muscle protein post- exercise, and this is especially important in older adults. In the above article by Dickinson, the important finding is the following (At least in older adults): The ingestion of 10 grams of essential amino acids containing either 1.85 or 3.5 grams of Leucine, 1 hour after RE prolongs the anabolic response of aging muscle and facilities improved sensitivity of aging muscle to amino acids,...

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