Sarcopenia of Aging and Its Metabolic Impact

Helen Karakelides, K. Sreekumaran Nair

Research output: Chapter in Book/Report/Conference proceedingChapter

189 Scopus citations


Sarcopenia contributes significantly to the morbidity, decrease in quality of life, and health care costs in the elderly. It is characterized by a decrease in muscle mass and strength, starting as early as the fourth decade of life in humans. Distinct muscle changes include a decrease in type 2 muscle fibers and a decrease in myosin heavy chains IIa and IIx mRNA levels. In addition, a decrease in whole body protein turnover, mixed muscle protein synthesis, myosin heavy chain synthesis, and mitochondrial protein synthesis have been reported. Different tissues and organs display different responses to aging, with more oxidative tissue generally having more age-related changes. Exercise has been shown to increase strength, aerobic capacity, and muscle protein synthesis, as well as to increase muscle mitochondrial enzyme activity in both young and older people; however, exercise does not reverse all age-related changes. The metabolic effects of sarcopenia include a decrease in resting metabolic rate secondary to decreased fat-free mass and decreased physical activity, leading to a higher prevalence of insulin resistance, type 2 diabetes mellitus, dyslipidemia, and hypertension. The way in which age-related changes in hormone levels affect muscle remains to be fully understood. The effect of replacing those hormones on sarcopenia has led to some conflicting results, but further investigations are ongoing.

Original languageEnglish (US)
Title of host publicationCurrent Topics in Developmental Biology
EditorsGerald Schatten
Number of pages26
StatePublished - 2005

Publication series

NameCurrent Topics in Developmental Biology
ISSN (Print)0070-2153

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology


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