Muscle: Use it or Lose it!
The term “Sarcopenia” comes from the Greek root “poverty of flesh”. Defined in the more modern sense, it is the loss of muscle mass and muscle function. Sarcopenia is a condition that has strong implications for aging individuals and comes at a high price to our healthcare system. It was estimated in the year 2000, that sarcopenia-related healthcare costs were around $18.5 billion dollars (1.5% of total U.S. healthcare expenses) . If anything, these costs have increased over the past two decades. Muscle mass can account for up to 40% of total body weight, and skeletal muscle has been considered a group of organs that immensely influences one’s overall health. The status of an individual’s skeletal muscle health can give inference to susceptibility to metabolic risk factors including obesity, type 2 diabetes, cardiovascular disease, and dyslipidemia .
For those who are inactive, sarcopenia is a condition that is a likely reality. It happens gradually over time rather than overnight. Primarily, each decade after age 30, loss of muscle mass has been seen to be anywhere from 3-8%, with an average of .2kg of lean weight lost per year (0.44lb). Muscle loss accelerates after age 50 at 5-10% each decade, with an average of .4kg of lean weight lost per year (0.88lb). With chronic muscle mass loss comes the accompanied decline in metabolic rate each decade - a drop of 2-3% . Keeping muscle mass during aging will mean keeping the ability to better burn calories at rest.
What can be done to mitigate and reverse sarcopenia?
Two main things: Adequate dietary protein and physical activity/muscle contraction
1. Adequate dietary protein. Generally, protein needs are going to INCREASE as we age. The recommended dietary allowance of 0.8g/kg/day (~55 grams per day for a 150lb individual) does not take into account the diminished ability of our bodies to make use of dietary protein that comes with aging process - a concept known as anabolic resistance. Another factor that the standard RDA for protein does not take into account is protein quality - overall, animal sources are more digestible and have a more abundant amino acid profile than other sources. Research has shown that a protein intake in the range of 1.2-1.6g/kg/day (~82-110 grams/day for a 150lb individual) leads to better health outcomes than 0.8g/kg/day .
2. Physical activity/ muscle contraction. Yes, cardiovascular exercise is great (150 minutes of moderate intensity, e.g. walking OR 75 minutes of vigorous activity e.g. running or jogging)! Get it done. The type of physical activity though, often overlooked, but plays the largest role is preventing sarcopenia, is resistance training. In addition to cardiovascular exercise, resistance training should be done 2-3 days per week with at least moderate intensity, challenging major muscle groups progressively over time . Taking steps to eat well and be active can make all the difference in aging gracefully!
DISCLAIMER: This is not medical or nutritional advice of any kind or a substitute therefore, but rather, this post is for educational purposes. Always consult your physician or qualified health professional before making any changes that can impact your health.
Janssen et al. 2004. The Healthcare Costs of Sarcopenia in the United States. Journal of the American Geriatrics Society, 52(1), 80–85. https://doi.org/10.1111/j.1532-5415.2004.52014.x
Move More; Sit Less. (2020, October 7). Centers for Disease Control and Prevention. https://www.cdc.gov/physicalactivity/basics/adults/index.htm
Phillips, S. M., Chevalier, S., & Leidy, H. J. (2016). Protein “requirements” beyond the RDA: implications for optimizing health. Applied Physiology, Nutrition, and Metabolism, 41(5), 565–572. https://doi.org/10.1139/apnm-2015-0550
Westcott, W. L. (2012). Resistance Training is Medicine. Current Sports Medicine Reports, 11(4), 209–216. https://doi.org/10.1249/jsr.0b013e31825dabb8
Photo credit: Jillian Wanik DCN, Storrs, 6th February 2017