Effects of Combined Resistance and Power Training on Cognitive Function in Older Women: A Randomized Controlled Trial

Effects of resistance exercise and whey protein supplementation on cognitive function in older men: secondary analysis of a randomised, double-blind, placebo-controlled trial

PURPOSE

Ageing is associated with cognitive decline. This study investigated the individual and combined effects of resistance exercise (RE) and whey protein supplementation (PRO) on cognitive function in older men.

METHODS

In a pooled-groups analysis, 36 older men (age: 67 ± 4 years) were randomised to either RE (2 x/week; n = 18) or no exercise (NE; n = 18), and either PRO (2 × 25 g/d whey protein isolate; n = 18) or control (CON, 2 × 23.75 g maltodextrin/d; n = 18). A sub-analysis was also conducted between RE + CON (n = 9) and RE + PRO (n = 9). At baseline and 12 weeks, participants completed a battery of neuropsychological tests (CANTAB; Cambridge Cognition, UK) and neurobiological, inflammatory, salivary cortisol and insulin sensitivity biomarkers were quantified.

RESULTS

PRO improved executive function z-score (+0.31 ± 0.08) greater than CON (+0.06 ± 0.08, P = 0.03) and there was a trend towards improved global cognitive function (P = 0.053). RE and RE + PRO did not improve any cognitive function domains (p ≥ 0.07). RE decreased tumor necrosis factor-alpha (P = 0.02) and interleukin-6 (P = 0.048) concentrations compared to NE, but changes in biomarkers did not correlate with changes in cognitive domains. Muscle strength (r = 0.34, P = 0.045) and physical function (ρ = 0.35-0.51, P < 0.05) outcomes positively correlated with cognitive function domains at baseline, but only Δskeletal muscle index correlated with Δepisodic memory (r = 0.34, P = 0.046) following the intervention.

CONCLUSION

In older men, PRO improved cognitive function, most notably executive functioning. RE did not improve any cognitive function domains but did decrease biomarkers of systemic inflammation. No synergistic effects were observed.

Effects of Exercise-Induced Changes in Myokine Expression on the Tumor Microenvironment

In this narrative review, we summarize the direct and indirect effects that myokines have on the tumor microenvironment. We took studies of various cancer types and species into account. Systematic reviews and meta-analyses that matched the search terms were also considered. We searched databases for six months. As a narrative approach was chosen, no data was analyzed or reanalyzed. The goal of this narrative review is to create an overview on the topic to identify research gaps and answer the questions as to whether myokine expression may be relevant in cancer research in regard to the tumor microenvironment. Six commonly known myokines were chosen. We found strong links between the influence exercise has on interleukin-6, oncostatin M, secreted protein acidic and rich in cysteine, and irisin in the context of tumor progression and inhibition via interactions with the tumor microenvironment. It became clear that the effects of myokines on the tumor microenvironment can vary and contribute to disease progression or regression. Interactions among myokines and immune cells must also be considered and require further investigation. To date, no study has shown a clear connection, while multiple studies suggest further investigation of the topic, similar to the effects of exercise on myokine expression.

Effects of resistance training associated with a verbal fluency task on physical performance and cognitive function in frail nursing home residents

OBJECTIVES

Studies examining the effects of dual-task resistance training (RT) on nursing-home residents are still scarce. To add knowledge to this field, the present study compared the effects of 12-week RT and RT plus cognitive task (COG) programs on physical performance and cognitive function in a sample of frail nursing home residents.

METHODS

This is an experimental study that combined data from two studies that examined older adults living in nursing home residences in Brazil. Exercise groups performed a 12-week RT protocol that included four exercises, with 3-4 times (sets) of 8-10 repetitions at 70 %-75 % of 1-repetition maximum (1RM), twice a week. The RT+COG group evoked as many words was possible for specific categories during concentric actions of the squat on the chair (until 90° knee flexion) and seated unilateral knee extension exercises. Global cognitive function and physical performance were evaluated using the Mini-Mental State Examination (MMSE) and Short Physical Performance Battery (SPPB) tests, respectively.

RESULTS

After interventions, participants in the RT+COG and RT groups had significantly greater lower-limb muscle strength compared with the control group (CG). Those in the RT+COG group had greater tandem performance in comparison to RT and CG groups.

CONCLUSIONS

Our findings indicate that RT preserves lower-limb muscle strength in frail nursing home residents, regardless of performance of cognitive tasks. Better balance was exclusively observed in the RT+COG, whereas significant improvements in mobility status were only found in the RT group. The present investigation was based on a small sample of nursing home residents. Larger and more structured studies are necessary to confirm our results.

Cognitive Enhancement Strategies for Older Adults: An Evaluation of Different Training Modalities to Improve Executive Function-A Systematic Review and Meta-Analysis

(1) Background: The aging population is expected to triple by 2050. Executive functions decline with age, impacting daily tasks, and this is associated with neurodegenerative diseases. Aerobic and resistance exercises positively affect cognitive function in older adults by influencing growth markers. However, the modalities of exercise and the optimal parameters for maximum cognitive benefits remain unclear. (2) Methods: A meta-analysis of randomized clinical trials (RCTs) was conducted. The systematic search was on slowing cognitive decline and performed in the PubMed/MEDLINE and Cochrane Library databases. Articles were included if participants were ≥65 years, healthy, and performing resistance or aerobic exercise, and they were excluded if there was a combination of training and if they have neurological disease or cognitive impairment. (3) Results: The search strategy found a total of 1635 studies. After removing duplicates and assessing the inclusion and exclusion criteria, eight articles were included in the meta-analysis, with a total of 463 healthy older adults analyzed. No significant differences between the intervention groups and the control groups after the aerobic or resistance programs were found. (4) Conclusions: Aerobic exercise interventions improved executive function more than resistance training in older adults, but without statistically significant differences. This can serve as a guide to see, with caution, whether we need a multidisciplinary approach to be more effective in improving the cortical health of older adults.

Effects of exercise interventions on cognitive functions in healthy populations: A systematic review and meta-analysis

Chronic exercise intervention is a non-pharmacological therapy suggested to improve cognitive function in various populations. However, few meta-analyses have assessed the cognitive benefits associated with all FITT-VP variables (exercise frequency, intensity, bout duration time, type, volume or total intervention length, and progression) in healthy populations by age. Thus, this meta-analysis assessed the effects of each FITT-VP variable on cognitive function in healthy children, adults, and older adults. This study followed PRISMA guidelines. After searching PubMed and the Web of Science, we included 54 randomized controlled trials to examined the effects of FITT-VP variables on five cognitive domains: global cognition, executive function, memory, attention, and information processing. Moderation analyses assessed the effects by age and by each exercise variables. Exercise benefitted overall cognition and all subcognitive domains. Aerobic and resistance exercise showed the greatest benefits on global cognition and executive function respectively, whereas mind-body exercise benefitted memory. Among all populations, older adults showed the greatest benefits of exercise on global cognition, executive function, and memory compared with controls. Additional studies are needed to assess the effects of exercise on attention and information processing. This meta-analysis offers new insights on the relationships between cognition and FITT-VP exercise variables in healthy populations.

The impact of resistance training on brain-derived neurotrophic factor and depression among older adults aged 60 years or older: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This systematic review and meta-analysis aimed to investigate the impact of resistance training on brain-derived neurotrophic factor (BDNF) and depression among older adults aged 60 years or older.

METHOD

Four electronic databases were systematically searched.

RESULTS

A total of 11 randomized controlled trials, with a pooled sample of 868 participants, met our inclusion criteria. Meta-analysis demonstrated that resistance training significantly improved circulating BDNF levels (mean difference; MD: 0.73 ng/ml; 95% CI [0.04, 1.42]; p = 0.04). Additionally, resistance training was associated with significant improvements in depression (standardized mean difference; SMD: -0.38; 95% CI [- 0.62, -0.14]; p = 0.002).

DISCUSSION

These findings suggest that resistance training may be an effective intervention for improving BDNF levels and reducing depression symptoms in older adults. Further research is needed to confirm these findings and to investigate the underlying mechanisms.

High-velocity resistance training improves executive function in mobility-limited older adults

OBJECTIVES

To examine the effect of high-velocity resistance training (HVRT) on the executive function of middle-aged and older adults with and without mobility limitations.

METHODS

Participants (n = 41, female: 48.9%) completed a supervised 12-week HVRT intervention (2 sessions/week; at 40-60% of one-repetition maximum). The sample included 17 middle-aged adults (40-55 years); 16 older adults (>60 years) and 8 mobility-limited older adults (LIM). Executive function was assessed before and after the intervention period and was reported as z-scores. Maximal dynamic strength, peak power, quadriceps muscle thickness, maximal isometric voluntary contraction (MVIC), and functional performance were also measured pre and post intervention. Training-related adaptations in cognitive measures were calculated using a Generalized Estimating Equation model.

RESULTS

HVRT improved executive function in LIM (adjusted marginal mean differences [AMMD]: 0.21; 95%CI: 0.04, 0.38; p = 0.040) although no effect on middle-aged (AMMD: 0.04; 95%CI: -0.09; 0.17; p = 0.533) and older (AMMD: -0.11; 95%CI: -0.25; 0.02; p = 0.107) participants was observed. Improvements in maximal dynamic strength, peak power, MVIC, quadriceps muscle thickness, and functional performance were all associated with changes in executive function, and changes in the first four also seem to mediate the association between changes in functional performance and executive function.

CONCLUSIONS

HVRT-induced improvement in executive function of mobility-limited older adults were mediated by changes in lower-body muscle strength, power, and muscle thickness. Our findings reinforce the relevance of muscle-strengthening exercises to preserve cognition and mobility in older adults.

Association of exercise, brain-derived neurotrophic factor, and cognition among older women: A systematic review and meta-analysis

This systematic review and meta-analysis explored the effects of structured exercise regimens on brain-derived neurotrophic factor (BDNF) levels, a proxy for cognitive function, in older women. In this study, we collated evidence from the available clinical trials that reported BDNF levels and other outcomes following structured exercise regimens. Adhering to PRISMA Statement 2020 guidelines. PubMed/MEDLINE, Scopus, CINAHL Plus, and Cochrane were systematically searched using a combination of the following keywords: brain-derived neurotrophic factor, women, exercise, older, cognition, and/or cognitive. A random-effects model was applied; the statistical analysis was conducted in RevMan 5.4 (Cochrane). The risk of bias in the included trials was assessed using the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I) tool. Across 12 trials, 994 older women were included that were enrolled in different exercise regimens globally. Exercise regimens were categorized as aerobic, resistance/power training, aquatic, taekwondo, and multimodal and ranging from 30 to 60 min, 1-5 times per week across 5-24 weeks. Moderate improvement (Cohen's d: 0.44, 95% CI: 0.04-0.84, p = 0.03) was found in BDNF levels across all trials. There was a small yet insignificant improvement in mini-mental state examination (MMSE) scores (Cohen's d: 0.17, 95% CI: -0.79-1.13, p = 0.73). Aerobic exercise, aquatic exercise, and multimodal regimens showed significant association with improved BDNF levels but the sample size for individual exercise regimens was small A main limitation was the inclusion of 114 (10.3%) males in the data, introducing gender bias. This study provides novel insight into the association between various exercise regimens and BDNF levels among older women.

Mind body exercise improves cognitive function more than aerobic- and resistance exercise in healthy adults aged 55 years and older - an umbrella review

Exercise is often cited as a major factor contributing to improved cognitive functioning. As a result, the relationship between exercise and cognition has received much attention in scholarly literature. Systematic reviews and meta-analyses present varying and sometimes conflicting results about the extent to which exercise can influence cognition. The aim of this umbrella review was to summarize the effects of physical exercise on cognitive functions (global cognition, executive function, memory, attention, or processing speed) in healthy adults ≥ 55 years of age.Methods An umbrella review of systematic reviews with meta-analyses investigating the effect of exercise on cognition was performed. Databases (CINAHL, Cochrane Library, MEDLINE, PsycInfo, Scopus, and Web of Science) were searched from inception until June 2023 for reviews of randomized or non-randomised controlled trials. Full-text articles meeting the inclusion criteria were reviewed and methodological quality assessed. Overlap within included reviews was assessed using the corrected covered area method (CCA). A random effects model was used to calculate overall pooled effect size with sub-analyses for specific cognitive domains, exercise type and timing of exercise.Results Database searches identified 9227 reviews. A total of 20 met the inclusion criteria. They were based on 332 original primary studies. Overall quality of the reviews was considered moderate with most meeting 8 or more of the 16 AMSTAR 2 categories. Overall pooled effects indicated that exercise in general has a small positive effect on cognition (d = 0.22; SE = 0.04; p < 0.01). Mind-body exercise had the greatest effect with a pooled effect size of (d = 0.48; SE = 0.06; p < 0.001). Exercise had a moderate positive effect on global cognition (d = 0.43; SE = 0,11; p < 0,001) and a small positive effect on executive function, memory, attention, and processing speed. Chronic exercise was more effective than acute exercise. Variation across studies due to heterogeneity was considered very high.Conclusions Mind-body exercise has moderate positive effects on the cognitive function of people aged 55 or older. To promote healthy aging, mind-body exercise should be used over a prolonged period to complement other types of exercise. Results of this review should be used to inform the development of guidelines to promote healthy aging.Trial registration PROSPERO (CDR 42022312955).

Effects of multi-domain intervention on intrinsic capacity in older adults: A systematic review of randomized controlled trials (RCTs)

Intrinsic capacity is central to the maintenance of function in older adults, and maintaining optimal intrinsic capacity is of great importance to promote healthy aging. The purpose of this systematic review and meta-analysis was to analyze the impact of multi-domain interventions on intrinsic capacity in older adults, intervention components, and potential interactions between components. A total of 6740 published articles were screened until August 2022, and the review included 25 randomized controlled trials that analyzed populations, interventions, control groups, and outcomes. The meta-analysis showed improvements in the primary outcome indicators in the intervention group compared to the control group. These included increased scores on the Mini-Mental State Examination as an indicator of cognitive function, decreased scores on the Geriatric Depression Scale (GDS-15) as an indicator of psychological ability and increased scores on the Short Physical Performance Battery (SPPB) as an indicator of physical performance, with only the SPPB indicator analyzed showing greater heterogeneity. Significant improvements were also seen in the secondary indicators Time-to-Walk Test (TUG), gait speed, Chair Stand Test (CST), grip strength values and BMI. There was insufficient data for the Mini Nutritional Assessment (MNA) as an indicator of vitality to conduct a meta-analysis. Studies were of moderate to high quality. The results of this review indicate that multi-domain interventions can maintain the level of intrinsic capacity in older adults and are equally effective in older adults with declining self-care abilities.

Effects of Resistance Exercise on Neuroprotective Factors in Middle and Late Life: A Systematic Review and Meta-Analysis

Neuroprotective factors are involved in brain functioning. Although physical exercise has been shown to have a positive influence on these factors, the effect of resistance exercise on them is not well known. This systematic review and meta-analysis aimed to 1) estimate the efficacy of resistance exercise on major neuroprotective factors, such as insulin-like growth factor-1 (IGF-1), brain-derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF), in middle and late life and 2) determine whether the effect is dose dependent. A systematic search was conducted in CINAHL, Cochrane CENTRAL, MEDLINE, Scopus, PEDro, SPORTDiscus, and Web of Science up to November 2022. Random effects models were used to estimate standardized mean differences (SMDs) and their respective 95% confidence intervals (CI) for the effect of resistance exercise on peripheral IGF-1, BDNF or VEGF levels in older adults. Thirty randomized clinical trials with 1247 subjects (53.25% women, 45-92 years) were included in the systematic review, and 27 were selected for the meta-analysis. A significant effect of resistance exercise on IGF-1 levels was observed (SMD: 0.48; 95% CI: 0.27, 0.69), being more effective when performing 3 sessions/week (SMD: 0.55; 95% CI: 0.31, 0.79) but not on BDNF (SMD: 0.33; 95% CI: -0.29, 0.94). The effect on VEGF could not be determined due to the scarcity of studies. Our data support the resistance training recommendation in middle and late life, at a frequency of at least 3 sessions/week, to mitigate the neurological and cognitive consequences associated with aging, mainly through IGF-1.

Resistance Training Combined With Cognitive Training Increases Brain Derived Neurotrophic Factor and Improves Cognitive Function in Healthy Older Adults

Background

The present study compared the effects of a traditional resistance training (TRT) and resistance training combined with cognitive task (RT + CT) on body composition, physical performance, cognitive function, and plasma brain-derived neurotrophic factor (BNDF) levels in older adults.

Methods

Thirty community-dwelling older adults were randomized into TRT (70.0 ± 8.1; 25% men) and RT + CT (66.3 ± 4.6; 31% men). Exercise groups performed a similar resistance training (RT) program, twice a week over 16 weeks. Cognitive Training involved performing verbal fluency simultaneously with RT. Exercise sessions (eight resistance exercises) were performed 2–3 sets, 8–15 repetitions at 60%–70% of 1-repetition maximum (1RM). Body composition, physical function, cognitive performance, and BDNF levels were assessed before and after intervention period.

Results

The physical performance was similarly improved in response to both TRT and RT + CT (p = 0.001). However, exclusive improvements on cognitive function (p < 0.001) and BDNF levels (p = 0.001) were observed only after RT + CT.

Conclusion

The RT program associated with a cognitive task, improved physical and cognitive performance in healthy older adults.

Calanus Oil Supplementation Does Not Further Improve Short-Term Memory or Brain-Derived Neurotrophic Factor in Older Women Who Underwent Exercise Training

Purpose

In our study, we examined changes in short-term episodic memory and brain-derived neurotrophic factor (BDNF) in women after an exercise program alone or in combination with omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation.

Patients and Methods

Fifty-five healthy elderly women (65–80 years) were randomly split into two groups: in the first group were women attending an exercise program while taking wax esters-rich oil (Calanus) supplementation (n = 28) and in the other group were women undergoing the same exercise program while taking placebo (n = 27). The 16-week exercise program consisted of functional circuit training (twice a week) and Nordic walking lessons (once a week). Short-term episodic memory was evaluated by the Czech screening Test “Pojmenování OBrázků A jejich Vybavení” (POBAV) baseline and after the program lasting 16 weeks.

Results

Our results show that short-term memory significantly improved following the exercise program, but there was no added value in using n-3 PUFA supplements. BDNF values did not differ between baseline and follow-up in either group. However, there was a statistically significant positive relationship between relative change (%) in the POBAV test and VO₂peak in the placebo group (r = 0.49).

Conclusion

Despite the added value of n-3 PUFA supplementation not being proven, our results may strengthen the importance of physical activity in averting age-related memory decline and dementia.

Strength-Cognitive Training: A Systemic Review in Adults and Older Adults, and Guidelines to Promote "Strength Exergaming" Innovations

Background

Despite functional and cognitive benefits, few adults and older adults do strength training twice per week with sufficient intensity. Exercise-based active video games (exergaming) may amplify the cognitive benefits of exercise and increase adherence and motivation toward training. However, the benefits of a well-defined and monitored dose of strength training, executed simultaneously or sequentially with a cognitive element, has received little attention. In this study we have two aims: First, to systematically gather the available evidence; second, to suggest possible ways to promote strength exergaming innovations.

Methods

We systematically reviewed randomized controlled trials using simultaneous or sequent combined strength and cognitive training or strength exergaming to improve cognitive or functional outcomes in adults and older adults.

Results

After screening 1,785 studies (Google Scholar, ACM Digital Library, IEEE Xplore Library, PsycARTICLES, Scopus, Cochrane Library and PubMed) we found three eligible studies. Of the two studies using sequent strength and cognitive training, one showed improved functionality, but the other showed negative effects on cognition. The third study using simultaneous intervention, reported a positive influence on both cognition and function, when compared with either strength training alone or a control group. Moderate level of evidence was showed on GRADE analysis.

Conclusion

The existing little evidence suggests that strength and cognitive training improves cognition and function in adults and older adults. The following suggestions may help to promote further innovation: (1) ensure minimal dosage of strength training (30-60 min, 2 × /week), (2) use machine-based strength training devices to control volume and intensity (to prevent cognitive components from interfering with strength training), (3) include power training by using cognitive tasks requiring rapid reactions, and (4) add cognitive memory tasks (to extend the cognitive benefits of strength training per se), and (5) include motivational exergame elements to increase adherence.

Psychological, Physiological, and Physical Effects of Resistance Training and Personalized Diet in Celiac Women

Background

Gluten intolerance is a systemic process of autoimmune nature; it develops in genetically predisposed subjects with gluten ingestion. The only treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). This study was designed to evaluate adherence to a GFD, risk of an eating disorder, and nutritional status in adult CD patients undergoing different interventions.

Methods

A total of 28 Spanish women, aged 40 years or more, took part in a randomized controlled trial. Each group received a different intervention: group 1, gluten-free nutrition plan + exercise (GFD + E); group 2, gluten-free nutrition plan (GFD); group 3, celiac controls (NO-GFD); and group 4, non-celiac controls (CONTROL). The training was prescribed by a sport scientist. It was based on resistance training with elastic bands; beforehand a warm-up was performed and the resistance was increased progressively. The variables studied were adherence to the GFD, risk of eating disorders, blood values, and body composition.

Results

Celiac women with personalized nutritional planning presented greater adherence to a gluten-free diet (p < 0.001). Regarding leukocytes, significant differences were observed between the GFD and control groups (p = 0.004). Perimeters and folds did not decrease significantly.

Conclusion

Women with celiac disease who follow an adapted and personalized diet have a better adherence to a GFD compared to those who follow a non-professional diet, and therefore have a better immune system status (blood leukocytes).

Resistance training improves cognitive function in older adults with different cognitive status: a systematic review and Meta-analysis

The present study investigated the impact of resistance training (RT) on cognitive function in older adults with different cognitive status by conducting a systematic review and meta-analysis of intervention studies. We performed a literature search with no restriction on publication year in MEDLINE, Embase, CINAHL, SPORTDiscus, and AgeLine from inception up to August 2020. Experimental studies investigating the impact of RT on the cognitive function of cognitively healthy (CH) and cognitively impaired (CI) older adults (≥60 years) were included for analysis. Eighteen studies were included in the final analysis, of which ten studies investigated CH community-dwelling older adult, seven studies investigated CI older adults, and one study investigated both. RT significantly improved overall cognitive function in both CH (SMD = 0.54; 95% CI = 0.00 to 1.08, P = 0.047) and CI (SMD = 0.60; 95% CI = 0.21 to 1.16, P = 0.005) older adults. However, short-term memory was only improved in CH older adults (MD = -0.20; 95% CI = -0.25 to -0.15, P < 0.00001). In conclusion, RT improved overall cognitive function in CH and CI older adults, whereas short-term memory, assessed by the digit span of the WAIS III, was only significantly improved in CH older adults.

Cross-sectional and longitudinal associations between adherence to Mediterranean diet with physical performance and cognitive function in older adults: A systematic review and meta-analysis

OBJECTIVES

The present study investigated the association between adherence to Mediterranean diet (MeDi) and physical performance and cognitive function in older adults.

METHODS

We conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated older adults aged 60+ years and assessed adherence to MeDi diet using validated composite scores. Observational studies, including cross-sectional, case-control, and longitudinal cohort studies, if crude baseline data was available, which investigated as a primary or secondary outcome the association of MeDi diet adherence with physical performance and/or cognitive function in non-demented older adults were included in the cross-sectional analysis. For the longitudinal analysis, case-control and longitudinal cohort studies that investigated the longitudinal associations between adherence to MeDi diet with the incidence of mild cognitive impairment (MCI), dementia, and/or Alzheimer's disease (AD), and/or changes in physical performance and cognition in non-demented older adults were included. Studies published in other languages than English were excluded. Studies were retrieved from MEDLINE, SCOPUS, CINAHL, and AgeLine databases until May 19, 2021. The risk of bias was evaluated using the Newcastle - Ottawa Quality Assessment Scale (NOS). A pooled effect size was calculated based on standard mean differences (SMD), log odds ratio (OR) and log risk ratio (RR). This study is registered on PROSPERO (CRD42021250254).

RESULTS

Nineteen cross-sectional studies that investigated 19.734 community-dwelling and institutionalized older adults free of disability and dementia were included. A high adherence to MeDi was cross-sectionally associated with better walking speed (SMD = 0.42; 95 % Confidence Interval (CI) = 0.12-0.72, P = 0.006; I² = 65 %, P = 0.06), knee muscle strength speed (SMD = 0.26; 95 % CI = 0.17-0.36, P < 0.00001; I² = 0 %, P = 0.69), global cognition (SMD = 0.24; 95 % CI = 0.15-0.33, P < 0.00001; I² = 85 %, P < 0.00001), and memory (SMD = 0.18; 95 % CI = 0.13-0.25, P < 0.00001; I² = 100 %, P < 0.00001). The association between MeDi adherence and global cognition remained significant after stratifying the analysis by the region where the study was conducted, MeDi diet adherence composite score, and Mini Mental State Examination (MMSE). Studies had a moderate to low risk of bias. In relation to longitudinal analysis, thirty-four prospective studies with an average follow-up period that varied from 3.0 to 12.6 years and investigated 98.315 community-dwellers were included. Results indicated that older adults with high MeDi scores had a lower decline in global cognition RR = 0.26; 95 % CI = 0.23-0.29, P < 0.00001; I² = 100 %, P < 0.00001). In contrast, no significant associations between MeDi and mobility, MCI, dementia were found. A low risk of bias was found in the longitudinal studies.

DISCUSSION

Findings of the present study indicated that high adherence to MeDi was cross-sectionally associated with physical performance and cognitive function. Results of the pooled analysis of longitudinal studies revealed that high adherence to MeDi reduced the risk of global cognitive decline in non-demented older adults. However, no significant associations between MeDi adherence and the incidence of mobility problems, MCI, and dementia were found. Although important, our findings should be carefully interpreted due to the presence of heterogeneity and publication bias.

Evidence-based recommendations for resistance and power training to prevent frailty in community-dwellers

Frailty is a reversible state of reduced resilience to stressful events resulting from a multisystem impairment of the human body. As frailty progresses, people become more vulnerable to numerous adverse events, including falls and fractures, cognitive decline, disability, hospitalization, nursing home placement, and death. As such, substantial health care costs are associated with frailty. These features have led to the recognition of frailty as a public health problem. The identification of strategies for the management of frailty has, therefore, become a topic of extensive instigation. In this context, resistance (RT) and power training (PT) have received considerable attention, and experts in the field have recently suggested that both training modalities may improve frailty-related parameters. However, most studies have only included robust people and investigated frailty as a secondary outcome, so that current literature only allows RT and PT preventive programs against frailty to be designed. Here, we provide evidence-based critical recommendations for the prescription of RT and PT programs against incident frailty in community-dwellers.

Protein Intake and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis

Introduction:

The present study investigated the association between protein intake and cognitive function in older adults.

Methods:

We performed a literature search with no restriction on publication year in MEDLINE, SCOPUS, CINAHL, AgeLine from inception up to October 2020. Observational studies that investigated as a primary or secondary outcome the association of protein intake and cognitive function in older adults aged ⩾60 years were included.

Results:

Nine cross-sectional studies that investigated a total of 4929 older adults were included in the qualitative analysis. Overall cognitive function was examined in 6 studies. Four investigations reported null associations and 2 studies found that older adults with a high protein intake had higher global cognitive function than their counterparts. Results from the meta-analysis suggested that there were no significant associations between protein consumption and global cognitive function in older adults, regardless of gender. Three studies investigated other cognitive domains. Memory and protein intake were significantly and positively correlated in all studies. In addition, visuospatial, verbal fluency, processing speed, and sustained attention were positively associated with protein consumption in 1 study each.

Conclusion:

No significant associations between protein intake and global cognitive function were observed in neither qualitative nor quantitative analyses. The association between protein consumption with multiple other cognitive domains were also tested. As a whole, 3 studies reported a positive and significant association between high protein intake and memory, while 1 study observed a significant and positive association with visuospatial, verbal fluency, processing speed, and sustained attention.

Effects of Progressive Resistance Training on Cognition and IGF-1 Levels in Elder Women Who Live in Areas with High Air Pollution

The aim of this study was to determine the effects of a muscular strength programme on the levels of insulin-like growth factor-1 (IGF-1) and cognitive status in elder women with mild cognitive impairment who lived in areas of high air pollution. A total of 157 women participated in the study, distributed in four groups: Active/Clean (AC n = 38) and Active/Pollution (AP n = 37), who carried out a progressive resistance training programme for 24 months, and Sedentary/Clean (SC n = 40) and Sedentary/Pollution (SP n = 42). Maximum strength in the upper and lower limbs (1RM), cognition (Mini-Mental Scale Examination (MMSE)) and blood IGF-1 were evaluated. At the beginning of the intervention, there were no differences between the groups in the assessed variables. The active groups which carried out the resistance training programme (AC and AP), registered better results in IGF-1 than the sedentary groups. These differences were statistically significant in AC vs. SC (p < 0.01) and AP vs. SC (p < 0.05). Regarding MMSE, group AC registered the highest score increases (+8.2%) (significantly better than the other groups), while group SP worsened (−7%) significantly compared to the other three groups. In conclusion, resistance training had a positive effect on IGF-1, while sedentary behaviour and air pollution had a negative effect on cognitive status.