Age-Related Skeletal Muscle Dysfunction Is Aggravated by Obesity: An Investigation of Contractile Function, Implications and Treatment

Abstract

Obesity is a global epidemic and coupled with the unprecedented growth of the world’s older adult population, a growing number of individuals are both old and obese. Whilst both ageing and obesity are associated with an increased prevalence of chronic health conditions and a substantial economic burden, evidence suggests that the coincident effects exacerbate negative health outcomes. A significant contributor to such detrimental effects may be the reduction in the contractile performance of skeletal muscle, given that poor muscle function is related to chronic disease, poor quality of life and all-cause mortality. Whilst the effects of ageing and obesity independently on skeletal muscle function have been investigated, the combined effects are yet to be thoroughly explored. Given the importance of skeletal muscle to whole-body health and physical function, the present study sought to provide a review of the literature to: (1) summarise the effect of obesity on the age-induced reduction in skeletal muscle contractile function; (2) understand whether obesity effects on skeletal muscle are similar in young and old muscle; (3) consider the consequences of these changes to whole-body functional performance; (4) outline important future work along with the potential for targeted intervention strategies to mitigate potential detrimental effects.

Sarcopenia, Obesity, and Sarcopenic Obesity: Relationship with Skeletal Muscle Phenotypes and Single Nucleotide Polymorphisms

“…This is somewhat surprising as most studies report a higher muscle strength in obese [32,61]. We have no explanation for this unexpected finding, but we did see a lower MVC KE /VL ACSA reflecting a lower muscle quality that has regularly been reported in obesity [62,63] and has been suggested to be due to accumulation of intramuscular fat, impaired muscle activation [32], and systemic inflammation [32,64]. Our findings suggest that obesity causes a reduced muscle quality, even in non-sarcopenic older women.…”

Phase Angle Is a Marker of Muscle Quantity and Strength in Overweight/Obese Former Athletes

“…The current outcomes showed that PhA accounted for more than 30% of skeletal muscle mass, remaining a significant predictor regardless of age sex, and fat mass. Indeed, fat mass was considered as a confounding variable since previous studies observed detrimental effects of excessive body fat to a loss of muscle mass and strength [ 21 ], as well as to a state of inflammation and therefore to a reduction in PhA [ 20 ]. In addition, PhA remained a borderline predictor of upper- and lower-body strength variance independently of age, sex, and fat mass.…”

“…The importance of muscle quantity and strength for health status is well established [ 2 , 36 , 37 ]. Muscle mass and strength have been shown to decrease with age, and this decline is mediated by body fat since this component reduces the contractile performance of skeletal muscle [ 2 , 21 ]. Not only the relationship between adiposity and metabolic disease is recognized but also the pathogenic potential of adipose tissue, particularly by excessive adipocyte hypertrophy, interacts with other body organs such as liver and skeletal muscle [ 38 ].…”

“…In fact, skeletal muscle mass represents functional mass and positively contributes to strength production [ 18 ], while an optimal level of aerobic fitness contributes to generate and maintain power output during repeated high-intensity efforts and to recover [ 19 ]. However, at the end of the athletic career, these parameters undergo a decline, a process that may also be accelerated if body fat becomes high, as observed in former elite athletes [ 4 , 20 , 21 ]. In addition, many athletes who retired from their sports careers do not sustain a regular exercise routine, contributing to a decrement in physical fitness [ 22 , 23 ].…”

The Critical Role of Oxidative Stress in Sarcopenic Obesity

“…Further, since SO is a multifactorial disease, the treatment must also be multifactorial [31]. The treatment could include exercise training and nutritional, pharmacological, psychological, and social interventions [5,6,12,48,[154][155][156]. One problem is the elevated cost of a multifactorial intervention, which health insurance generally does not cover.…”