The impact of obesity on muscle function in older adults: from clinical evaluation to lifestyle management

In the geriatric population, obesity and sarcopenia constitute two important public concerns due to their association with disability, loss of independence, comorbidity, and mortality. Only few studies previously evaluated the impact of obesity on the in vivo muscle strength, power, and physical function in the older population, particularly on the lower extremities. This is surprising, since particularly the decline of lower body physical function negatively affects important daily activities. In older adults the role of obesity and adipose tissue on muscle function decline is complex and not completely understood. Furthermore, the possible contribution of lower limb muscles in the evaluation of muscle weakness has been poorly investigated. Finally, various studies exist on the possible approaches using exercise and nutrition to treat and to ameliorate obesity, dynapenia and sarcopenia; discrepancies are instead presented on the potential beneficial effects associated with the supplementations compared to exercise alone, leaving open questions about the best treatments to adopt in this population. Therefore, the goals of this thesis are: i) to determine the impact of obesity on the in vivo lower limbs muscle strength and function in older adults of both sexes; ii) to investigate the associations between lower limbs muscle strength and function and the handgrip dynamometer and the possible contribution to predict the appendicular muscle mass; iii) to propose an intervention protocol aimed at improving or reversing obesity and sarcopenia condition. Chapter one explored the literature around the effects of obesity in the geriatric population. A particular emphasis is made on the important role of maintaining and assessing muscle strength, muscle mass and function. Additionally, an overview of different strategies for treating or reversing obesity and sarcopenia through exercise and nutrition are provided. Chapter two presents the consequences of obesity on the lower limbs’ muscles, adding new reference data of knee extensors and knee flexors strength and power in geriatric population of both sexes. Chapter three focuses on the tools used for evaluating muscle weakness. In this context, the role of handgrip dynamometer as a proxy of muscle strength is argued with a comprehensive narrative review and an experimental study. In the latter, the associations between upper vs lower limbs muscle strength and physical function are discussed looking at the possible sex differences in geriatric population. Chapter four describes the preliminary results on the role of a 5-month controlled diet plus strength training alone or amino acids supplementation in older adults with obesity, dynapenia and sarcopenia. After the intervention, the changes in several outcomes (i.e., on body composition, upper and lower limbs muscle strength and power, physical performance) are described, by comparing the different interventional groups. Lastly, chapter five outlines the main results of each study and presents a general conclusion with proposals for future directions needed on these research topics

The Role of Obesity, Body Composition, and Nutrition in COVID-19 Pandemia: A Narrative Review

The coronavirus disease 2019 (COVID-19) pandemic has spread worldwide, infecting nearly 500 million people, with more than 6 million deaths recorded globally. Obesity leads people to be more vulnerable, developing worse outcomes that can require hospitalization in intensive care units (ICU). This review focused on the available findings that investigated the link between COVID-19, body composition, and nutritional status. Most studies showed that not only body fat quantity but also its distribution seems to play a crucial role in COVID-19 severity. Compared to the body mass index (BMI), visceral adipose tissue and intrathoracic fat are better predictors of COVID-19 severity and indicate the need for hospitalization in ICU and invasive mechanical ventilation. High volumes of epicardial adipose tissue and its thickness can cause an infection located in the myocardial tissue, thereby enhancing severe COVID-related myocardial damage with impairments in coronary flow reserve and thromboembolism. Other important components such as sarcopenia and intermuscular fat augment the vulnerability in contracting COVID-19 and increase mortality, inflammation, and muscle damage. Malnutrition is prevalent in this population, but a lack of knowledge remains regarding the beneficial effects aimed at optimizing nutritional status to limit catabolism and preserve muscle mass. Finally, with the increase in patients recovering from COVID-19, evaluation and treatment in those with Long COVID syndrome may become highly relevant

Exercise and physical performance in older adults with sarcopenic obesity: A systematic review

BackgroundSarcopenic obesity is characterized by low muscle mass and high body fat; prevalence increases with age, particularly after age 65 years. For this systematic literature review we searched scientific databases for studies on exercise interventions for improving physical performance in adults with sarcopenic obesity; also, we identified potential gaps in clinical practice guidelines that need to be addressed.MethodsWe followed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The databases were searched for studies published through November 2021 that measured physical performance in adults with sarcopenic obesity.ResultsMost of the studies applied a strength training protocol in which improvement was noted post-treatment on the Time Chair Rise (TCR), 30-s Chair Stand, and Single Leg Stance (SLS) tests. Discrepancies between the studies were observed when resistance training was combined with or without elastic bands or electromyostimulation, as measured with the Short Physical Performance Battery (SPPB), Physical Performance Test (PPT), Gait Speed, and Timed Up & Go (TUG) test. Post-intervention SPPB, PPT, and gait speed scores showed an increase or maintenance of performance, while TUG test scores were higher according to one study but lower according to another.ConclusionsEngagement in physical exercise, and resistance training in particular, can improve or maintain physical performance in adults with sarcopenic obesity. Study samples should include more men. A future area of focus should be the impact of different types of training (aerobic, power training, combined modalities). Finally, studies with longer intervention periods and follow-up periods are needed to gain a better understanding of the effectiveness of exercise on physical function in adults with sarcopenic obesity

Sprint running: how changes in step frequency affect running mechanics and leg spring behaviour at maximal speed

The purpose of this study was to investigate the changes in selected biomechanical variables in 80-m maximal sprint runs while imposing changes in step frequency (SF) and to investigate if these adaptations differ based on gender and training level. A total of 40 athletes (10 elite men and 10 women, 10 intermediate men and 10 women) participated in this study; they were requested to perform 5 trials at maximal running speed (RS): at the self-selected frequency (SFs) and at SF \ub115% and \ub130%SFs. Contact time (CT) and flight time (FT) as well as step length (SL) decreased with increasing SF, while kvert increased with it. At SFs, kleg was the lowest (a 20% decrease at \ub130%SFs), while RS was the largest (a 12% decrease at \ub130%SFs). Only small changes (1.5%) in maximal vertical force (Fmax) were observed as a function of SF, but maximum leg spring compression (\u394L) was largest at SFs and decreased by about 25% at \ub130%SFs. Significant differences in Fmax, \u394y, kleg and kvert were observed as a function of skill and gender (P\ua0<\ua00.001). Our results indicate that RS is optimised at SFs and that, while kvert follows the changes in SF, kleg is lowest at SFs

Knee flexor and extensor torque ratio in elderly men and women with and without obesity: a cross-sectional study

Background: With aging and obesity lower limb torque deteriorates. Importantly, the ratio between knee flexor (KF) and extensor (KE) torque is an indicator of joint stability. Aims: We compared KF torque and KF/KE ratio in older subjects of both sexes with obesity (OB) or without (NOB) obesity. Methods: The maximal torque during KE and KF isokinetic contractions were evaluated at: 60, 90, 150, 180 and 210 deg/s in 89 elderly (68 \ub1 5 years) subjects with NOB (BMI < 30 kg/m2) and OB (BMI 65 30 kg/m2). Values were normalised for body weight (BW) and leg lean mass (i.e., muscle quality). Results: At all speeds men had higher absolute KF values (P < 0.001). When values were normalised for BW, sex differences remain in favour of men (P < 0.001) with lower values in both groups with OB than NOB (P < 0.001). Muscle quality and KF/KE ratio were lower in OB than NOB (P < 0.001). Conclusions: The KF torque and KF/KE ratio decline with aging and with OB. In all groups, the KF/KE ratio was below the joint stability threshold. Thus, exercise physiologists should include exercises designed to train both KE and KF in older subjects with OB

Prolonged unsupervised Nordic walking and walking exercise following six months of supervision in adults with overweight and obesity: a randomised clinical trial

Background and aims: This study is a randomized trial that examined the effects of 6 months of unsupervised Nordic walking (NW) and walking (W) exercise following 6 months of supervised training in overweight/obese adults. Methods and results: After a 6-month program of diet and supervised training participants (n = 27) of NW (66 \ub1 7 yrs, body mass index (BMI) 34 \ub1 5) and W (66 \ub1 8 yrs, BMI 32 \ub1 5) group continue the training without supervision for other 6 months. Steps count and mean heart rate (HRmean) were performed in each session; anthropometric and body composition, aerobic capacity and strength of the upper and lower limbs were evaluated at baseline, after 6 months of supervised and 6 months of unsupervised training. In the unsupervised training, monthly sessions and steps count decreased over time in both groups (p &lt; 0.05), with no significant changes in HRmean. Compared to the supervised phase, adherence decreased significantly only in the W group in the last 3 months of unsupervised training. Compared to baseline in both groups BMI did not change, but W group lost total fat; only the NW group maintained (p &lt; 0.05) the gains in arm curl (33%) and chair stand (31%); both groups improved in six-minute walking test (p &lt; 0.05). Conclusion: Despite unsupervised training was not effective for a further increase in performance, participants, especially in NW, maintained some of the improvements achieved during the supervision. However, the presence of instructor that guides training, may enhance adherence and health benefits of NW and W exercise. Clinical trial registration: clinicaltrials.gov Identifier: NCT03212391 (July 11, 2017)

Full characterisation of knee extensors' function in ageing: effect of sex and obesity

Muscle function is a marker of current and prospective health/independence throughout life. The effects of sex and obesity (OB) on the loss of muscle function in ageing remain unresolved, with important implications for the diagnosis/monitoring of sarcopenia. To characterise in vivo knee extensors' function, we compared muscles torque and power with isometric and isokinetic tests in older men (M) and women (W), with normal range (NW) of body mass index (BMI) and OB

Type 2 Diabetes Related Mitochondrial Defects in Peripheral Mononucleated Blood Cells from Overweight Postmenopausal Women

Type 2 diabetes (T2D) is a multisystem disease that is the subject of many studies, but the earliest cause of the disease has yet to be elucidated. Mitochondrial impairment has been associated with diabetes in several tissues. To extend the association between T2D and mitochondrial impairment to blood cells, we investigated T2D-related changes in peripheral mononucleated blood cells’ (PBMCs) mitochondrial function in two groups of women (CTRL vs. T2D; mean age: 54.1 ± 3.8 vs. 60.9 ± 4.8; mean BMI 25.6 ± 5.2 vs. 30.0 ± 5), together with a panel of blood biomarkers, anthropometric measurements and physiological parameters (VO2max and strength tests). Dual-energy X-ray absorptiometry (DXA) scan analysis, cardio-pulmonary exercise test and blood biomarkers confirmed hallmarks of diabetes in the T2D group. Mitochondrial function assays performed with high resolution respirometry highlighted a significant reduction of mitochondrial respiration in the ADP-stimulated state (OXPHOS; −30%, p = 0.006) and maximal non-coupled respiration (ET; −30%, p = 0.004) in PBMCs samples from the T2D group. The total glutathione antioxidant pool (GSHt) was significantly reduced (−38%: p = 0.04) in plasma samples from the T2D group. The fraction of glycated hemoglobin (Hb1Ac) was positively associated with markers of inflammation (C-reactive protein-CRP r = 0.618; p = 0.006) and of dyslipidemia (triglycerides-TG r = 0.815; p p = 0.034; ET r = −0.529; p = 0.024). The results obtained in overweight postmenopausal women from analysis of PBMCs mitochondrial respiration and their association with anthropometric and physiological parameters indicate that PBMC could represent a reliable model for studying T2D-related metabolic impairment and could be useful for testing the effectiveness of interventions targeting mitochondria

The Mini Sarcopenia Risk Assessment (MSRA) Questionnaire score as a predictor of skeletal muscle mass loss

Background Previous studies showed a strong relationship between reduction of appendicular muscle mass and worsening disability; hence, accuracy in assessing muscle mass is considered a key feature for a sarcopenia screening tool. Aim The aim of the study was to evaluate if the 7 items of Mini Sarcopenia Risk Assessment (MSRA) questionnaire predict muscle mass loss in a population of community-dwelling elderly subjects over a 5.5-y follow-up. Methods The study included 159 subjects, 92 women and 67 men aged 71.5 +/- 2.2 years and with mean body mass index of 26.7 +/- 4.0 kg/m(2). Appendicular skeletal muscle mass (ASMM) as measured with Dual-Energy X-ray absorptiometry (DXA), was obtained at baseline and after 2 and 5.5 years of follow-up where the skeletal muscle index (SMI) was calculated. Results A significant reduction of ASMM and SMI was observed at two and 5.5 years of follow-up, in both, men and women. Repeated-measures analysis of variance (ANOVA) found a significant time effect on ASMM for both subjects with MSRA &gt; 30 and &lt;= 30 (P &lt; 0.01 and P &lt; 0.001). The group x time interaction was significant (P &lt; 0.001), after even considering separately subjects with normal muscle mass and low muscle mass at baseline (P &lt; 0.05 and P = 0.005). Similar results were obtained for SMI. Considering only the subjects with normal SMI at baseline, subjects with MSRA questionnaire &lt;= 30 showed 5.7 (95% CI 1.73-19.03) higher risk of exceeding the low muscle mass threshold. Conclusion In a population of community-dwelling elderly men and women, MSRA score of 30 is predictive of a steeper decline in ASMM and SMI and of a higher risk of exceeding the low muscle mass EWGSOP threshold

Worsening Disability and Hospitalization Risk in Sarcopenic Obese and Dynapenic Abdominal Obese: A 5.5 Years Follow-Up Study in Elderly Men and Women.

Background/Objectives: A general lack of studies comparing the effect of both dynapenic abdominal obesity and sarcopenic obesity on worsening disability and hospitalization risk should be recognized. The aim of the current study was to evaluate, with a 5.5-year follow-up, the prognostic value of sarcopenic obesity and dynapenic abdominal obesity definitions on worsening disability and hospitalization risk in a sample of older adults. Subjects/Methods: In 177 women and 97 men aged 68-78 years, the following outcomes were evaluated at baseline: appendicular skeletal muscle mass (ASMM), percent fat mass (FM%), leg isometric strength, body mass index (BMI), lipid profile, vitamin D3, albumin, fibrinogen, glycemia, physical activity level, income, smoking status, and comorbidities. The rate of reported disabilities and hospitalization were also assessed at baseline, 1, 2, 3, and 5.5-years follow-up. The study population was classified into: (i) non-sarcopenic/obese (NS/O), sarcopenic/non-obese (S/NO), sarcopenic/obese (S/O), non-sarcopenic/non-obese (NS/NO, reference category) according to relative ASMM/FM% tertiles; (ii) non-dynapenic/abdominal obese (ND/AO), dynapenic/non-abdominal obese (D/NAO), dynapenic/abdominal obese (D/AO), non-dynapenic/non-abdominal obese (ND/NAO, reference category) according to muscle strength/waist circumference tertiles. Results: The prevalence of D/AO and S/O was 12.0 and 8.0%, respectively. Only 2 subjects were both D/NAO and S/O (0.8%). D/NAO subjects showed a worsening disability risk of 1.69 times (95% CI: 1.11-2.57), ND/AO subjects showed a 2-fold increased risk (95% CI: 1.34-2.98), while being D/AO more than trebled the risk, even after adjustment for confounding factors (HR: 3.39, 95%; CI: 1.91-6.02). By dividing the study population according to the relative ASMM/FM% tertiles, no groups showed an increased risk of worsening disability. The hospitalization risk, even after adjustment for potential confounders, was 1.84 (95% CI: 1.06-3.19) for D/AO. Dividing the study population according to the relative ASMM/FM% tertiles, no groups showed increased risk of hospitalization. Conclusions: Our results showed that dynapenic abdominal obesity and sarcopenic obesity seem to indicate two distinct phenotypes associated with different health risk profiles. The distribution of participants in waist circumference and muscle strength tertiles allowed for a more accurate risk stratification for worsening disability and hospitalization