Effects of Resistance Exercise with Instability on Cognitive Function (REI Study): A Proof-Of-Concept Randomized Controlled Trial in Older Adults with Cognitive Complaints

The Effects of Appropriate Perioperative Exercise on Perioperative Neurocognitive Disorders: a Narrative Review

Perioperative neurocognitive disorders (PNDs) are now considered the most common neurological complication in older adult patients undergoing surgical procedures. A significant increase exists in the incidence of post-operative disability and mortality in patients with PNDs. However, no specific treatment is still available for PNDs. Recent studies have shown that exercise may improve cognitive dysfunction-related disorders, including PNDs. Neuroinflammation is a key mechanism underlying exercise-induced neuroprotection in PNDs; others include the regulation of gut microbiota and mitochondrial and synaptic function. Maintaining optimal skeletal muscle mass through preoperative exercise is important to prevent the occurrence of PNDs. This review summarizes current clinical and preclinical evidence and proposes potential molecular mechanisms by which perioperative exercise improves PNDs, providing a new direction for exploring exercise-mediated neuroprotective effects on PNDs. In addition, it intends to provide new strategies for the prevention and treatment of PNDs.

Comparison of the Electromyography Activity during Exercises with Stable and Unstable Surfaces: A Systematic Review and Meta-Analysis

The effect of electromyographic (EMG) activity on agonist muscles during exercises performed on stable and unstable surfaces remains uncertain. We aimed to review the literature regarding the comparison of the EMG activity of the agonist muscles of exercises performed on stable and unstable surfaces. Eighty-six studies that evaluated the EMG activity of 1783 individuals during exercises for the lower limbs, upper limbs, and core were included. The EMG activities of the pectoralis major (SMD = 0.28 [95% CI 0.09, 0.47]) and triceps brachii muscles (SMD = 0.45 [95% CI 0.25, 0.66]) were significantly increased when the unstable device was added to the exercise. Likewise, the EMG activity of all core muscles showed a significant increase with the unstable surface during the exercises, such as the rectus abdominis (SMD = 0.51 [95% CI 0.37, 0.66]), external oblique (SMD = 0.44 [95% CI 0.28, 0.61]), internal oblique (SMD = 1.04 [95% CI 0.02, 2.07]), erector spinae (SMD = 0.37 [95% CI 0.04, 0.71]), and lumbar multifidus (SMD = 0.35 [95% CI 0.08, 0.61]). However, the lower limb muscles did not show greater EMG activity during the exercise with unstable surfaces compared to the stable surface. In conclusion, unstable conditions increase the EMG activity of some upper limb and core muscles compared to a stable surface.

Physical activity improves the visual-spatial working memory of individuals with mild cognitive impairment or Alzheimer's disease: a systematic review and network meta-analysis

Objective

Our network meta-analysis aimed to ascertain the effect of physical activity on the visual-spatial working memory of individuals with mild cognitive impairment and Alzheimer's disease as well as to propose tailored exercise interventions for each group.

Methods

Employing a frequentist approach, we performed a network meta-analysis to compare the effectiveness of different exercise interventions in improving the visual-spatial working memory of individuals with mild cognitive impairment and Alzheimer's disease. Subsequently, we explored the moderating variables influencing the effectiveness of the exercise interventions through a subgroup analysis.

Results

We included 34 articles involving 3,074 participants in the meta-analysis, comprised of 1,537 participants from studies on mild cognitive impairment and 1,537 participants from studies on Alzheimer's disease. The articles included exhibited an average quality score of 6.6 (score studies) and 6.75 (reaction time [RT] studies), all passing the inconsistency test (p > 0.05). In the mild cognitive impairment literature, mind-body exercise emerged as the most effective exercise intervention (SMD = 0.61, 95% CI: 0.07-1.14). In Alzheimer's disease research, aerobic exercise was identified as the optimal exercise intervention (SMD = 0.39, 95% CI: 0.06-0.71).

Conclusion

The results of the subgroup analysis suggest that the most effective approach to enhancing the visual-spatial working memory of individuals with mild cognitive impairment entails exercising at a frequency of three or more times per week for over 60 min each time and at a moderate intensity for more than 3 months. Suitable exercise options include mind-body exercise, multicomponent exercise, resistance exercise, and aerobic exercise. For individuals with Alzheimer's disease, we recommend moderately intense exercise twice per week for over 90 min per session and for a duration of 3 months or longer, with exercise options encompassing aerobic exercise and resistance exercise.

Does High-Velocity Resistance Exercise Elicit Greater Physical Function Benefits Than Traditional Resistance Exercise in Older Adults? A Systematic Review and Network Meta-Analysis of 79 Trials

BACKGROUND

A systematic review and network meta-analysis was undertaken to examine the effectiveness of different modes of resistance exercise velocity in fast walking speed, timed-up and go, 5-times sit-to-stand, 30-second sit-to-stand, and 6-minute walking tests in older adults.

METHODS

CINAHL, Embase, LILACS, PubMed, Scielo, SPORTDiscus, and Web of Science databases were searched up to February 2022. Eligible randomized trials examined the effects of supervised high-velocity or traditional resistance exercise in older adults (ie, ≥60 years). The primary outcome for this review was physical function measured by fast walking speed, timed-up and go, 5-times sit-to-stand, 30-second sit-to-stand, and 6-minute walking tests, while maximal muscle power and muscle strength were secondary. A random-effects network meta-analysis was undertaken to examine the effects of different resistance exercise interventions.

RESULTS

Eighty articles describing 79 trials (n = 3 575) were included. High-velocity resistance exercise was the most effective for improving fast walking speed (standardized mean difference [SMD] -0.44, 95% confidence interval [CI]: 0.00 to 0.87), timed-up and go (SMD -0.76, 95% CI: -1.05 to -0.47), and 5-times sit-to-stand (SMD -0.74, 95% CI: -1.20 to -0.27), while traditional resistance exercise was the most effective for 30-second sit-to-stand (SMD 1.01, 95% CI: 0.68 to 1.34) and 6-minute walking (SMD 0.68, 95% CI: 0.34 to 1.03).

CONCLUSION

Our study provides evidence that resistance exercise velocity effects are specific in older adults, as evidenced by physical function test dependence. We suggest that prescriptions based on the velocity of contraction should be individualized to address the specific functional needs of participants.

Effects of instability resistance training on static postural control of cognitively impaired older adults

BACKGROUND: Mounting evidence has demonstrated functional and cognitive-related benefits after Instability Resistance Training (IRT) in individuals, healthy as wellas patients presenting with neurological disorders. However, whether IRT may play a significant role in the postural control of older adults has not been established. OBJECTIVE: To evaluate the effects of 12- weeks of IRT on static postural control of older adults with subjective cognitive impairment. METHODS: In this randomized controlled trial, a total of 67 participants (aged 65 years and older) were randomly assigned to either 12 weeks of IRT (n= 22), traditional resistance training (RT) (n= 23), or a health education control group (CON) (n= 22). Static postural control was assessed using a force platform that recorded the displacement amplitude of the center of pressure (CoP) in the anteroposterior (AP) and mediolateral (ML) directions in bipedal support (30 seconds) with eyes open and closed. RESULTS: All groups increased AP displacement in the conditions of eyes open and closed. During the eyes-closed condition, only the IRT group increased the ML displacement. No between-group differences were detected in any postural control (p> 0.05). CONCLUSIONS: 12 weeks of IRT does not improve the static postural control in older adults with cognitive impairment.

Optimal dose and type of exercise to improve cognitive function in older adults: A systematic review and bayesian model-based network meta-analysis of RCTs

OBJECTIVE

To examine the dose-response relationship between overall and specific types of exercise with cognitive function in older adults.

DESIGN

Systematic Review and Bayesian Model-Based Network Meta-Analysis.

DATA SOURCES

Systematic search of MEDLINE, Web of Science, Scopus, PsycINFO and SPORTDiscus.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomized controlled trials of exercise interventions in participants aged 50 years or over, and that reported on at least one global cognition outcome.

RESULTS

The search returned 1998 records, of which 44 studies (4793 participants; 102 different effect sizes) were included in this review with meta-analysis. There was a non-linear, dose-response association between overall exercise and cognition. We found no minimal threshold for the beneficial effect of exercise on cognition. The estimated minimal exercise dose associated with clinically relevant changes in cognition was 724 METs-min per week, and doses beyond 1200 METs-min per week provided less clear benefits. We also found that the dose-response association was exercise type dependent, and our results show that clinically important effects may occur at lower doses for many types of exercise. Our findings also highlighted the superior effects of resistance exercises over other modalities.

CONCLUSIONS

If provided with the most potent modalities, older adults can get clinical meaningful benefits with lower doses than the WHO guidelines. Findings support the WHO recommendations to emphasise resistance training as a critical component of interventions for older adults.

Exercise for the prevention and treatment of neurocognitive disorders: new evidence and clinical recommendations

PURPOSE OF REVIEW

As current pharmacological treatments of dementia have only modest effects, nonpharmacological treatments like exercise interventions have attracted much research interest. This review summarizes recent evidence regarding the efficacy of exercise in preventing and treating neurocognitive disorders.

RECENT FINDINGS

Recent evidence suggests that exercise may prevent cognitive impairment in older adults with normal cognition. Besides, it may slow down the deterioration in older adults who have mild cognitive impairment (MCI) and dementia. But inconsistent findings have been reported, and larger randomized controlled trials are required to confirm its treatment value. This article also reviews existing evidence-based clinical guidelines advising on the optimal format and intensity of exercise interventions for older adults with different cognitive functions.

SUMMARY

There is a growing body of evidence supporting the cognitive benefits of exercise for older adults with normal cognition, MCI, and dementia. Exercise is a relatively safe and low-cost lifestyle intervention and should be recommended for older adults to prevent dementia and treat cognitive impairment. However, as the factors affecting the efficacy of exercise in improving cognition are complex, exercise prescription should be individually tailored.

Association between physical functioning with cognition among community-dwelling older adults: a cross-sectional study

Objective: Declines in physical and cognitive functioning often co-exist through aging. Gait-related parameters have been related to cognitive function, although it is unclear whether other measures of physical functioning are similarly related to cognition. Here, we analyzed the relationship between physical functioning with cognition in older adults. Methods: In total, 116 participants were included (M age = 69 years, SD = 6; 71% women). We quantified cognitive functioning using the Montreal Cognitive Assessment (MoCA) and executive functioning tasks (Digit Span Forward minus Backward and verbal fluency tests). Physical function measures included gait speed, Short-physical Performance Battery (SPPB), five-times Sit-to-Stand Test, the Timed Up and Go (TUG) test, the Six-minute Walk Test (6MWT), and lower extremity muscle strength. We used multiple linear regression analyses to explore the association between cognitive measures and each measure of physical functioning, adjusting for age, sex, education, and RCT. Results: We observed a positive association between muscle strength and the MoCA (b = 0.84, SE = 0.40, 95%CI 0.05–1.64) after controlling for covariates. Significant associations were also found between the five-times-sit-to-stand test (b = -0.63, SE = 0.26, 95%CI -1.15–-0.12), TUG (b = -1.13, SE = 0.57, 95%CI -2.26–-0.01), 6MWT (b = 0.04, SE = 0.02, 95%CI 0.01–0.07), and lower extremity muscle strength (b = 1.92, SE = 0.93, 95%CI 0.09–3.77) with the FAS verbal fluency test, and between the TUG (b = -0.62, SE = 0.24, 95%CI -1.11–-0.14) with animal naming. Conclusion: In community-dwelling older adults, higher levels of muscle strength, dynamic balance and cardiorespiratory fitness were positively related with global cognition and executive control measures.

Additional Functional Performance Gains After 24-Week Unstable Strength Training With Cognitive Training in Community-Dwelling Healthy Older Adults: A Randomized Trial

The authors investigated the effects of unstable strength training (UST) without or with cognitive training (C+UST) on functional performance in community-dwelling older adults. A total of 50 participants were randomly assigned (1:1) to either 24 weeks of thrice-weekly UST (n = 25) or C+UST (n = 25). All participants performed moderate-intensity strength exercises using unstable surfaces, and C+UST participants simultaneously received cognitive training in addition to UST. Primary outcomes included measures of functional performance: single- and dual-task timed up and go tests. Secondary outcomes included dynamic balance, mobility, handgrip strength, flexibility, quality of life, and concern about falling. The authors observed similar improvements on functional performance through the interventions. The C+UST group experienced additional gains at completion (single-task timed up and go: -0.90 s, 95% confidence interval [-2.38, -0.03]; dual-task timed up and go: -4.80 s, 95% confidence interval [-8.65, -0.95]) compared with the UST group. Moreover, significant differences were observed in mobility (sitting-rising test: -1.34, 95% confidence interval [-2.00, -0.20]) at 24 weeks. Both exercise modes improved single-task functional performance, while adding cognitive-training-optimized dual-task functional performance gains.