The influence of prolonged strength training upon muscle and fat in healthy and chronically diseased older adults

Physical exercise, cognition, and brain health in aging

Exercise training is an important strategy to counteract cognitive and brain health decline during aging. Evidence from systematic reviews and meta-analyses supports the notion of beneficial effects of exercise in cognitively unimpaired and impaired older individuals. However, the effects are often modest, and likely influenced by moderators such as exercise training parameters, sample characteristics, outcome assessments, and control conditions. Here, we discuss evidence on the impact of exercise on cognitive and brain health outcomes in healthy aging and in individuals with or at risk for cognitive impairment and neurodegeneration. We also review neuroplastic adaptations in response to exercise and their potential neurobiological mechanisms. We conclude by highlighting goals for future studies, including addressing unexplored neurobiological mechanisms and the inclusion of under-represented populations.

Influence of exercise prescription intervention based on WeChat on glycolipid metabolism and fitness of suboptimal-health teachers

Exercise is an effective means to promote health, but adherence is low. Due to the advantages of immediacy, economy and effectiveness, the use of WeChat social software has permeated into every aspect in daily life in China. To explore the influence of WeChat-based exercise prescription intervention mode on glycolipid metabolism and fitness of suboptimal-health teachers. 293 suboptimal-health teachers with senior professional titles were randomized to a control group (CG) or an experimental group (e.g.). The CG exercised on its own, while the e.g. adopted the exercise prescription intervention based on WeChat. The intervention period was 6 months. Finally, 264 cases were adhered to and completed, including 132 cases in the CG and 132 cases in the e.g.. The Suboptimal-Health Status Questionnaires-25 scores (SHSQ-25 scores), exercise adherence, subjective feelings, physical fitness, blood glucose and blood lipids were detected before and after intervention and compared between 2 groups. After the intervention, the SHSQ-25 scores in the e.g. was significantly decreased than those in the CG (P < .01). The complete exercise adherence in the e.g. was significantly higher than those in the CG (P < .01). After intervention, the subjective feelings of e.g. were significantly improved compared to CG (P < .05). The body shape, body function and physical quality in the e.g. was higher than those in the CG (P < .05). Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) decreased significantly in the e.g. but not in the CG (P < .05). Fasting blood glucose (FBG) decreased significantly in the e.g. but not in the CG, with a significant difference between groups (P < .05). The subjects in the e.g. were very satisfied with WeChat management. WeChat-based exercise prescription intervention could improve SHS, exercise adherence, subjective feelings, physical fitness and glycolipid metabolism.

Associations of resistance training levels with low muscle mass: a nationwide cross-sectional study in Korea

BACKGROUND

Low muscle mass is associated with adverse health outcomes such as functional decline and all-cause mortality. This study investigated the relationship between the risk of low muscle mass and the training period and/or frequency of resistance training (RT).

METHODS

We included 126,339 participants (81,263 women) from nationwide cohorts in Korea. Low muscle mass was defined based on the fat-free mass index. To investigate the presence of an inverse dose-response relationship between RT levels and the risk of low muscle mass, the training period (months) and frequency (per week) of RT were used. Multiple logistic regression models were used to assess the risk of low muscle mass according to the RT levels.

RESULTS

Prevalence rates for low muscle mass in our study population were 21.27% and 6.92% in men and women, respectively. When compared with not performing RT, performing RT for 3-4 days/week and ≥5 days/week decreased the risk of low muscle mass by 22% and 27%, respectively, and performing RT for 12-23 months and ≥24 months decreased the risk by 19% and 41%, respectively. When simultaneously considering both training period and frequency, performing RT for either 3-4 days/week or ≥5 days/week was significantly related to risk reduction, provided that the training period was at least 1 year. Importantly, performing RT for more than 2 years resulted in an additional risk reduction. However, there was no additional effect of performing RT for ≥5 days/week compared to 3-4 days/week, regardless of whether the RT duration was 1-2 years or more than 2 years.

CONCLUSIONS

Since performing RT for 5 days/week or more did not yield any additional effects on the risk of low muscle mass, performing RT for 3-4 days/week was sufficient to prevent low muscle mass. The effectiveness of this preventive measure can be further enhanced by engaging in long-term RT, specifically for more than 2 years.

End-to-end volumetric segmentation of white matter hyperintensities using deep learning

BACKGROUND AND OBJECTIVES

Reliable detection of white matter hyperintensities (WMH) is crucial for studying the impact of diffuse white-matter pathology on brain health and monitoring changes in WMH load over time. However, manual annotation of 3D high-dimensional neuroimages is laborious and can be prone to biases and errors in the annotation procedure. In this study, we evaluate the performance of deep learning (DL) segmentation tools and propose a novel volumetric segmentation model incorporating self-attention via a transformer-based architecture. Ultimately, we aim to evaluate diverse factors that influence WMH segmentation, aiming for a comprehensive analysis of the state-of-the-art algorithms in a broader context.

METHODS

We trained state-of-the-art DL algorithms, and incorporated advanced attention mechanisms, using structural fluid-attenuated inversion recovery (FLAIR) image acquisitions. The anatomical MRI data utilized for model training was obtained from healthy individuals aged 62-70 years in the Live active Successful Aging (LISA) project. Given the potential sparsity of lesion volume among healthy aging individuals, we explored the impact of incorporating a weighted loss function and ensemble models. To assess the generalizability of the studied DL models, we applied the trained algorithm to an independent subset of data sourced from the MICCAI WMH challenge (MWSC). Notably, this subset had vastly different acquisition parameters compared to the LISA dataset used for training.

RESULTS

Consistently, DL approaches exhibited commendable segmentation performance, achieving the level of inter-rater agreement comparable to expert performance, ensuring superior quality segmentation outcomes. On the out of sample dataset, the ensemble models exhibited the most outstanding performance.

CONCLUSIONS

DL methods generally surpassed conventional approaches in our study. While all DL methods performed comparably, incorporating attention mechanisms could prove advantageous in future applications with a wider availability of training data. As expected, our experiments indicate that the use of ensemble-based models enables the superior generalization in out-of-distribution settings. We believe that introducing DL methods in the WHM annotation workflow in heathy aging cohorts is promising, not only for reducing the annotation time required, but also for eventually improving accuracy and robustness via incorporating the automatic segmentations in the evaluation procedure.

Changes in Muscle Mass and Strength During Follow-Up After One-Year Resistance Training Interventions in Older Adults

ABSTRACT

Mertz, KH, Reitelseder, S, Rasmussen, MA, Bülow, J, Højfeldt, G, Jensen, M, Hjulmand, M, Lindberg, J, Kramer, MU, Bechshøft, R, and Holm, L. Changes in muscle mass and strength during follow-up after one-year resistance training interventions in older adults. J Strength Cond Res 37(10): 2064-2070, 2023-The aim of this study was to investigate if home-based resistance training compared with center-based resistance training was associated with better preservation of muscle mass and strength in older individuals, 6 months after the interventions ended. One hundred four healthy older individuals (>65 years) who had completed 1 year of either home-based light-intensity training with daily whey protein supplementation (LITW), center-based heavy resistance training with whey protein supplementation (HRTW), or daily whey protein supplementation alone (WHEY) returned for follow-up measurement 6 months after the interventions. Measures of muscle mass, strength, and power were assessed at the end of intervention as well as at follow-up. Furthermore, we compared changes in these parameters between subjects who continued resistance training (≥1 weekly training session) during follow-up (CONT) with those who stopped (STOP). Resistance training continuation during follow-up did not differ between HRTW and LITW (41 vs. 41%, P = 1.0) but was higher for both groups compared with WHEY (18%, P = 0.04-0.05). However, no between-group differences were observed between LITW/HRTW/WHEY in changes in muscle mass, strength, or power during follow-up. STOP was associated with a poorer preservation of quadriceps cross-sectional area compared with CONT (-1.7 cm 2 [-0.4 to -3.0], P = 0.01, effect size: 0.79). No effect of training continuation was observed on changes in muscle strength and power. In conclusion, maintenance of muscle mass and strength is not superior after home-based resistance training compared with center-based training. However, training continuation seems crucial for the maintenance of muscle mass, irrespective of the training intervention.

Resistance Training and Weight Loss in Older Adults: A Scoping Review

Resistance training (RT) is one of the most effective interventions available to older adults wishing to slow the progressive loss of muscle size and strength known to occur with age. Less is known about the ability of RT to resist the onset of an equally problematic condition related to increased age: obesity. The objective of this scoping review was to characterize current research associated with RT and weight loss in older adults, including protocols, feasibility, and gaps in current knowledge. We searched six databases using variations of the terms "resistance training," "weight loss," and "older adults" for experimental or quasi-experimental studies published in the year 2009 or later. Studies were included if they featured at least one treatment group with a mean age of > 65 years that engaged in an RT-only exercise protocol with no aerobic or high-intensity interval component. Of the 6102 references identified by the initial database search, 24 were retained for analysis. Older women and older adults with obesity or sarcopenic obesity were the most studied groups (n = 13), followed by healthy community-dwelling older adults (n = 11) and studies involving older adults and some aspect of either dietary control or pharmaceutical intervention (n = 8). Significant between-study heterogeneity was observed in the RT characteristics researchers thought optimal for improving body composition measures in older adults. Changes in body composition, rather than total body mass, were found to be the essential variables to consider when evaluating the effectiveness of an RT intervention aimed at reducing chronic disease in older adults. Weight loss alone appears to be an incomplete and problematic outcome measure for older adults, with changes in body composition (ratio of fat mass to lean mass) being the more appropriate variable to emphasize in this population. However, it is important to note that only one study, showing questionably reproducible findings, found a significant lean body mass gain. The lack of abundant high-quality evidence demonstrating combined RT and a healthy diet can lead to significant fat loss and lean body mass gain, coupled with high attrition rates observed in many of the studies reviewed, highlight the need for further rigorous research.

Preserved stem cell content and innervation profile of elderly human skeletal muscle with lifelong recreational exercise

Abstract

Muscle fibre denervation and declining numbers of muscle stem (satellite) cells are defining characteristics of ageing skeletal muscle. The aim of this study was to investigate the potential for lifelong recreational exercise to offset muscle fibre denervation and compromised satellite cell content and function, both at rest and under challenged conditions. Sixteen elderly lifelong recreational exercisers (LLEX) were studied alongside groups of age‐matched sedentary (SED) and young subjects. Lean body mass and maximal voluntary contraction were assessed, and a strength training bout was performed. From muscle biopsies, tissue and primary myogenic cell cultures were analysed by immunofluorescence and RT‐qPCR to assess myofibre denervation and satellite cell quantity and function. LLEX demonstrated superior muscle function under challenged conditions. When compared with SED, the muscle of LLEX was found to contain a greater content of satellite cells associated with type II myofibres specifically, along with higher mRNA levels of the beta and gamma acetylcholine receptors (AChR). No difference was observed between LLEX and SED for the proportion of denervated fibres or satellite cell function, as assessed in vitro by myogenic cell differentiation and fusion index assays. When compared with inactive counterparts, the skeletal muscle of lifelong exercisers is characterised by greater fatigue resistance under challenged conditions in vivo, together with a more youthful tissue satellite cell and AChR profile. Our data suggest a little recreational level exercise goes a long way in protecting against the emergence of classic phenotypic traits associated with the aged muscle.

Key points

The detrimental effects of ageing can be partially offset by lifelong self‐organized recreational exercise, as evidence by preserved type II myofibre‐associated satellite cells, a beneficial muscle innervation status and greater fatigue resistance under challenged conditions.

Satellite cell function (in vitro), muscle fibre size and muscle fibre denervation determined by immunofluorescence were not affected by recreational exercise.

Individuals that are recreationally active are far more abundant than master athletes, which sharply increases the translational perspective of the present study. Future studies should further investigate recreational activity in relation to muscle health, while also including female participants.

Functional improvements to 6 months of physical activity are not related to changes in size or density of multiple lower-extremity muscles in mobility-limited older individuals

Older adults are encouraged to engage in multicomponent physical activity, which includes aerobic and muscle-strengthening activities. The current work is an extension of the Vitality, Independence, and Vigor in the Elderly 2 (VIVE2) study - a 6-month multicenter, randomized, placebo-controlled trial of physical activity and nutritional supplementation in community dwelling 70-year-old seniors. Here, we examined whether the magnitude of changes in muscle size and quality differed between major lower-extremity muscle groups and related these changes to functional outcomes. We also examined whether daily vitamin-D-enriched protein supplementation could augment the response to structured physical activity. Forty-nine men and women (77 ± 5 yrs) performed brisk walking, muscle-strengthening exercises for the lower limbs, and balance training 3 times weekly for 6 months. Participants were randomized to daily intake of a nutritional supplement (20 g whey protein + 800 IU vitamin D), or a placebo. Muscle cross-sectional area (CSA) and radiological attenuation (RA) were assessed in 8 different muscle groups using single-slice CT scans of the hip, thigh, and calf at baseline and after the intervention. Walking speed and performance in the Short Physical Performance Battery (SPPB) were also measured. For both CSA and RA, there were muscle group × time interactions (P < 0.01). Significant increases in CSA were observed in 2 of the 8 muscles studied, namely the knee extensors (1.9%) and the hip adductors (2.8%). For RA, increases were observed in 4 of 8 muscle groups, namely the hip flexors (1.1 HU), hip adductors (0.9 HU), knee extensors (1.2 HU), and ankle dorsiflexors (0.8 HU). No additive effect of nutritional supplementation was observed. While walking speed (13%) and SPPB performance (38%) improved markedly, multivariate analysis showed that these changes were not associated with the changes in muscle CSA and RA after the intervention. We conclude that this type of multicomponent physical activity program results in significant improvements in physical function despite relatively small changes in muscle size and quality of some, but not all, of the measured lower extremity muscles involved in locomotion.

Gender Difference in the Relationship Between Pulse Pressure and Visceral Adiposity Index in Korean Adults

Background: This study was conducted to assess the association of pulse pressure (PP) and visceral adiposity index (VAI) by gender in Korean adults. Methods: This study used the data of 4960 adults at age ≥20 years, from the 2015 Korean National Health and Nutrition Examination Survey. Results: In the overall population (n = 4960), after adjustment for related variables and with quartile 1 of VAI as a reference, the odds ratios of high PP (PP >60 mmHg) was significantly higher in quartile 3 [1.32 (95% confidence interval [CI], 1.02-1.71)] and quartile 4 of VAI [1.40 (95% CI, 1.07-1.83)]. In women (n = 2784), the OR of high PP, with quartile 1 of VAI as a reference, was significantly higher in quartile 3 [2.36 (95% CI, 1.55-3.61)] and quartile 4 of VAI [2.70 (95% CI, 1.77-4.12)]. In men (n = 2176), high PP was not associated with the quartiles of VAI. In addition, after adjustment for related variables, the PP level was positively associated with the quartiles of VAI in the overall population (P < 0.001) and women (P < 0.001), but not in men (P = 0.316). Conclusions: VAI was positively associated with PP in Korean women, but not in Korean men.

Effect of resistance training with and without caloric restriction on visceral fat: A systemic review and meta-analysis

We performed a systematic review and meta-analysis to investigate the effect of resistance training (RT) with and without caloric restriction (CR) on visceral fat (VF). PubMed and Scopus were searched to identify original articles published through December 2020. Standardized mean differences and 95% confidence intervals (95% CIs) were determined, and separate analyses were conducted for RT versus control, and RT plus CR versus CR only. Thirty-four studies including 38 intervention arms and involving 2285 were included in the meta-analysis. RT effectively reduced VF [-24 (95% CI -0.34 to -0.13), p < 0.001; I²  = 4.17%, p = 0.40; 24 intervention arms] when compared with control. Based on subgroup analyses, reduction in VF was significant for individual with (p = 0.04) and without (p < 0.001) obesity as well as across medium-term (p = 0.001) and long-term (p = 0.002) interventions. Reduction in VF was significant for both middle-age (p = 0.03) and elderly (p = 0.001) adults but was not significant for pediatric (p = 0.08) participants. However, RT plus CR did not indicate superiority effect on VF [0.23 95% CI -0.04 to 0.51, p = 0.09; I²  = 58.76%, p = 0.003; 14 intervention arms] when compared with CR only. Our results confirm that RT may be effective for reducing VF, but adding RT with CR was not associated with a greater effect for reducing VF.

A Critical Systematic Review of Current Evidence on the Effects of Physical Exercise on Whole/Regional Grey Matter Brain Volume in Populations at Risk of Neurodegeneration

BACKGROUND

Despite the intriguing potential of physical exercise being able to preserve or even restore brain volume (grey matter volume in particular)-a tissue essential for both cognitive and physical function-no reviews have so far synthesized the existing knowledge from randomized controlled trials investigating exercise-induced changes of the brain's grey matter volume in populations at risk of neurodegeneration. Our objective was to critically review the existing evidence regarding this topic.

METHODS

A systematic search was carried out in MEDLINE and EMBASE databases primo April 2020, to identify randomized controlled trials evaluating the effects of aerobic training, resistance training or concurrent training on brain grey volume changes (by MRI) in adult clinical or healthy elderly populations.

RESULTS

A total of 20 articles (from 19 RCTs) evaluating 3-12 months of aerobic, resistance, or concurrent training were identified and included, involving a total of 1662 participants (populations: healthy older adults, older adults with mild cognitive impairment or Alzheimer's disease, adults with schizophrenia or multiple sclerosis or major depression). While few studies indicated a positive effect-although modest-of physical exercise on certain regions of brain grey matter volume, the majority of study findings were neutral (i.e., no effects/small effect sizes) and quite divergent across populations. Meta-analyses showed that different exercise modalities failed to elicit any substantial effects on whole brain grey volume and hippocampus volume, although with rather large confidence interval width (i.e., variability).

CONCLUSION

Altogether, the current evidence on the effects of physical exercise on whole/regional grey matter brain volume appear sparse and inconclusive, and does not support that physical exercise is as potent as previously proposed when it comes to affecting brain grey matter volume.

Associations Between Measures of Physical Activity and Muscle Size and Strength: A Systematic Review

Objective

To determine whether physical activity is associated with lower limb muscle size and strength within the general population.

Data Sources

Six databases were systematically searched from inception using 3 main constructs: lower extremity, muscle volume, and muscle strength.

Study Selection

Studies that measured physical activity (using either objective or subjective measurements), lower limb muscle size, and strength were included. Available discrete group data were standardized using previously published age- and sex-specific normative values prior to analysis.

Data Extraction

The final analysis included 47 studies from an initial yield of 5402 studies. Standardized scores for outcome measures were calculated for 97 discrete groups.

Data Synthesis

As anticipated, lower limb muscle size was positively correlated with lower limb muscle strength (r=0.26, P<.01; n=4812). Objectively measured physical activity (ie, accelerometry, pedometry) (n=1944) was positively correlated with both lower limb muscle size (r=0.30, P<.01; n=1626) and lower limb strength (r=0.24, P<.01; n=1869). However, subjectively measured physical activity (ie, questionnaires) (n=3949) was negatively associated with lower limb muscle size (r=–0.59, P<.01; n=3243) and lower limb muscle strength (r=–0.48, P<. 01; n=3882).

Conclusions

This review identified that objective measures of physical activity are moderately associated with lower limb muscle size and muscle strength and can, therefore, be used to predict muscle changes within the lower limbs associated with exercise-based rehabilitation programs.