Similar to the rest of the world, the United States is an aging society. Between the years 2000 and 2050, the aging population is projected to increase by 135% with over 100 million adults in the US over age 50 (1).
With increased age, there are many unwanted changes to the human body. Let's explore some strategies for combating age-related muscle loss (or sarcopenia). This subject is incredibly important for personal trainers who work with seniors.
What is Sarcopenia?
Sarcopenia is defined as the loss of skeletal muscle mass and strength, with muscle atrophy beginning at age 25 (2). Muscle is essential for maintaining muscle action, functional independence, managing daily activities, and living a healthy active lifestyle (3).
The average rate of muscle loss by age
Inactive adults experience a 3% to 8% loss of muscle mass per decade, accompanied by a lower resting metabolic rate, fat accumulation, and weight gain. Evidence also shows that strength declines at a greater rate than the loss of muscle of about 12-15% per decade after the fifth decade of life (4).
How to Prevent Muscle Loss for Seniors
There are several interventions that can help prevent the loss of skeletal muscle mass and strength associated with age, with resistance training, increased protein intake, and creatine supplementation being an important part of this process. Resistance training has the ability to decrease fat mass, as well as the ability to increase lean body mass, metabolism, and strength.
In addition, resistance training has shown to increase bone mineral density by as much as 1-3%, improve cardiovascular health by reducing resting blood pressure and cholesterol levels, along with improving cognitive abilities, glucose levels, and prevention of type 2 diabetes (5,6).
Nutritionally, there is substantial evidence that supports the consumption of high-quality protein well above the current Recommended Dietary Allowance (RDA) to achieve optimal health outcomes to promote healthy aging, increased muscle mass and strength, appetite regulation, and weight management. This current evidence suggests intakes in the range of at least 1.2 to 1.6 g/kg per day of high quality protein to achieve optimal health outcomes for active adults, compared to the current RDA Guidelines for protein of 0.8 g/kg per day for all adults including older ones (7).
It is important to note that the recommendations for increased protein consumption are based upon studies that include high quality, animal-based proteins that include lean animal sources that allow for the greatest protein content with fewer calories. In addition, with data being somewhat limited, there is increasing evidence that animal proteins, such as whey protein that contains the branched-chain amino acid leucine, promotes gains in lean mass through increased muscle protein synthesis and improve appetite control and satiety more so than some plant proteins (8).
Pre- and post-exercise protein supplementation via a protein shake can be effective to promote muscle anabolism. This additional protein should ideally be met through a balanced diet, and supplementation could be considered when protein intake from dietary sources is insufficient to meet the increased protein needs associated with resistance training (9). Creatine is a nutritional supplement that has been reported to be a safe ergogenic aid in healthy adults (10). Several studies have shown when creatine supplementation is used in combination with resistance training there was an increase in lean tissue mass and muscle strength in aging adults. In addition, creatine supplementation may show promise for improving bone mineral density (11,12).
In conclusion, it has been shown that age-related muscle loss and strength could impact functional independence, along with living an active, healthy lifestyle. Age-related muscle loss might contribute to health related concerns such as weight gain, cardiovascular diseases, metabolic diseases, and bone loss. Resistance training, core training, increased protein intake, and creatine supplementation in combination with resistance training has shown to be viable interventions for the aging population in the prevention of muscle loss and strength. It must be noted that these recommendations are for healthy adults with proper medical clearance and advice for dosing and administration.
References
1. Weiner, J., Tilly, J (2016) Population aging in the United States of America: implications for public programmes.
2. Cruz-Jentoft, A. J., Landi, F., Schneider, S. M., Zúñiga, C., Arai, H., Boirie, Y., & ... Cederholm, T. (2014). Prevalence of and interventions for sarcopenia in ageing adults: a systematic review. Report of the International Sarcopenia Initiative (EWGSOP and IWGS). Age And Ageing, 43(6), 748-759. doi:10.1093/ageing/afu115
3. Muhammad Mustafa, Q., & Muhammad Faiaz, Q. (2014). Strength Training Restores Morphological Changes Occur During Aging. Medical Channel, 20(1), 79-82.
4. Hunt, D., Chapa, D., Hess, B., Swanick, K., & Hovanec, A. (2015). The importance of resistance training in the treatment of sarcopenia. Journal Of Nursing Education & Practice, 5(3), 39-43 5p. doi:10.5430/jnep.v5n3p39
5. Westcott, W. (2012). Resistance Training is Medicine: Effects of Strength Training on Health. Current Sports Medicine Reports (American College Of Sports Medicine), 11(4), 209-216 8p. doi:10.1249/JSR.0b013e31825dabb8
6. Shaw, B. S., Shaw, I., & Brown, G. A. (2015). Resistance exercise is medicine: Strength training in health promotion and rehabilitation. International Journal Of Therapy & Rehabilitation, 22(8), 385-389 5p.
7. Phillips, S. M., Chevalier, S., & Leidy, H. J. (2016, 05). Protein “requirements” beyond the RDA: Implications for optimizing health1. Appl. Physiol. Nutr. Metab. Applied Physiology, Nutrition, and Metabolism, 41(5), 565-572. doi:10.1139/apnm-2015- 0550
8. Hector, A. J., Marcotte, G. R., Churchward-Venne, T. A., Murphy, C. H., Breen, L., von Allmen, M., & ... Phillips, S. M. (2015). Whey protein supplementation preserves postprandial myofibrillar protein synthesis during short-term energy restriction in overweight and obese adults. The Journal Of Nutrition, 145(2), 246-252. doi:10.3945/jn.114.200832
9. Zimmer, Raymond. (2005). Whey Protein- The Role of Protein Supplementation in Resistance Training. Nutrition Bytes, 10(2).
10. Cooper, R., Naclerio, F., Allgrove, J., & Jimenez, A. (2012). Creatine supplementation with specific view to exercise/sports performance: An update. J Int Soc Sports Nutr Journal of the International Society of Sports Nutrition, 9(1), 33. doi:10.1186/1550-2783-9-33
11. Candow, D. G., Vogt, E., Johannsmeyer, S., Forbes, S. C., & Farthing, J. P. (2015). Strategic creatine supplementation and resistance training in healthy older adults. Applied Physiology, Nutrition & Metabolism, 40(7), 689-694 6p. doi:10.1139/apnm- 2014-0498
12. Candow, D. G., Chilibeck, P. D., & Forbes, S. C. (2014). Creatine supplementation and aging musculoskeletal health. Endocrine, 45(3), 354-361. doi:10.1007/s12020- 013-0070-4
