Effects of Exercise in the Treatment of Alzheimer's Disease: An Umbrella Review of Systematic Reviews and Meta-Analyses

The impact of exercise on Alzheimer's disease progression

INTRODUCTION

The preventive effects of chronic physical exercise (CPE) on Alzheimer's disease (AD) are now admitted by the scientific community. Curative effects of CPE are more disputed, but they deserve to be investigated, since CPE is a natural non-pharmacological alternative for the treatment of AD.

AREAS COVERED

In this perspective, the authors discuss the impact of CPE on AD based on an exhaustive literature search using the electronic databases PubMed, ScienceDirect and Google Scholar.

EXPERT OPINION

Aerobic exercise alone is probably not the unique solution and needs to be complemented by other exercises (physical activities) to optimize the slowing down of AD. Anaerobic, muscle strength and power, balance/coordination and meditative exercises may also help to slow down the AD progression. However, the scientific evidence does not allow a precise description of the best training program for patients with AD. Influential environmental conditions (e.g. social relations, outdoor or indoor exercise) should also be studied to optimize training programs aimed at slowing down the AD progression.

Harnessing Passive Pulsatile Shear Stress for Alzheimer's Disease Prevention and Intervention

 Alzheimer's disease (AD) affects more than 40 million people worldwide and is the leading cause of dementia. This disease is a challenge for both patients and caregivers and puts a significant strain on the global healthcare system. To address this issue, the Lancet Commission recommends focusing on reducing modifiable lifestyle risk factors such as hypertension, diabetes, and physical inactivity. Passive pulsatile shear stress (PPSS) interventions, which use devices like whole-body periodic acceleration, periodic acceleration along the Z-axis (pGz), and the Jogging Device, have shown significant systemic and cellular effects in preclinical and clinical models which address these modifiable risks factors. Based on this, we propose that PPSS could be a potential non-pharmacological and non-invasive preventive or therapeutic strategy for AD. We perform a comprehensive review of the biological basis based on all publications of PPSS using these devices and demonstrate their effects on the various aspects of AD. We draw from this comprehensive analysis to support our hypothesis. We then delve into the possible application of PPSS as an innovative intervention. We discuss how PPSS holds promise in ameliorating hypertension and diabetes while mitigating physical inactivity, potentially offering a holistic approach to AD prevention and management.

Comparison of various exercise interventions on cognitive function in Alzheimer's patients: A network meta-analysis

OBJECTIVE

Exercise helps enhance cognitive function in Alzheimer's patients, although the most effective forms of exercise remain unknown.

METHODS

This network meta-analysis was registered in INPLASY (INPLASY202330066). According to predetermined criteria, this investigation comprised randomized controlled studies involving exercise therapies in people with Alzheimer's disease. The exercise intervention was ranked using surface under the cumulative ranking curve (SUCRA) and mean ranking, with the critical goal outcomes being overall cognition, executive function, and memory function.

RESULTS

Resistance exercise is the most likely strategy to be beneficial for slowing down overall cognitive function loss in Alzheimer's patients (72.4%). Additionally, multi-component exercise was the most effective way to improve executive function (30.4%). The only type of exercise that significantly affects memory function is resistance exercise. Memory is the cognitive function that is least responsive to exercise.

CONCLUSION

Resistance exercise may be an efficient intervention for overall cognitive function decline in patients with Alzheimer's and conjointly for their memory function. Multi-component exercise is more effective in improving executive function in patients with Alzheimer's disease.

Effects of Air Pollution on the Health of Older Adults during Physical Activities: Mapping Review

Atmospheric pollutants present environmental threats to health and have been investigated in different environments, such as highways, squares, parks, and gyms. These environments are frequented by older adults, who are considered fragile to the harmful impacts of pollution present in the air. The aim was to analyze the state of the art on the effects of air pollution on the health of older adults during physical activities (PAs) through a mapping review. The search was performed in PubMed, Web of Science, Scopus, and Cinahl databases until June 2022. Of the 10,109 studies initially identified, 58 met the inclusion criteria. The most investigated health outcome was cardiovascular disease, followed by respiratory outcomes. Particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), and ozone (O3) were the most investigated pollutants. Of the 75 health outcomes investigated, in 29, air pollution had harmful effects on the health of the older adults during the practice of PA, more frequently in cardiovascular diseases. In 25 outcomes, the beneficial effects of PA to the health of the older adults remained, despite exposure to high and low concentrations of pollutants, most often in terms of mental disorders. We conclude that poor air quality is a harmful factor for the health of older adults during the practice of PAs, more frequently in cardiovascular and respiratory diseases. On the other hand, for mental-health-related outcomes (depression and cognition), in most studies, the beneficial effects of PA in older adults were maintained, even after exposure to pollutants.

A Bibliometric and Visual Analysis of Exercise Intervention Publications for Alzheimer’s Disease (1998–2021)

Alzheimer’s disease (AD) is the most common cause of dementia worldwide, posing a considerable economic burden to patients and society as a whole. Exercise has been confirmed as a non-drug intervention method in the related literature on AD. However, at present, there are still few bibliometric studies on AD exercise research. In order to fill the gap, this paper aims to intuitively analyze the growth in AD exercise literature published from 1998 to 2021 using bibliometrics, providing historical insights for scientific research circles. The main source of literature retrieval is the Web of Science database. Using the Boolean operator tools “OR” and “AND” combined with keywords related to “exercise” and “Alzheimer’s disease”, we conducted a title search and obtained 247 documents. Using Microsoft Excel, Datawrapper, and Biblioshiny, this study carried out a bibliometric analysis of countries, institutions, categories, journals, documents, authors, and keyword plus terms. The study found that the number of papers published from 2016 to 2021 had the greatest increase, which may have been influenced by the Global Dementia Report 2015 and COVID-19. Interdisciplinary cooperation and the research results published in high-scoring journals actively promoted research and development in the AD exercise field. The United States and the University of Minnesota system play a central role in this field. In future, it will be necessary to explore the effectiveness and feasibility of multi-mode interventions on an active lifestyle, including exercise, in different groups and environments worldwide. This study may provide a direction and path for future research by showing the global overview, theme evolution, and future trends of research results in the AD exercise field.

Treadmill Exercise Modulates Intestinal Microbes and Suppresses LPS Displacement to Alleviate Neuroinflammation in the Brains of APP/PS1 Mice

Neuroinflammation occurs throughout the pathogenesis of Alzheimer’s disease (AD). Here, we investigated the effects of treadmill exercise on neuroinflammation in APP/PS1 transgenic AD mice and the potential involvement of microbe–gut–brain axis (MGB) mechanisms based on growing evidence that AD’s pathogenesis is correlated with a deterioration in the function of gut microbiota. APP/PS1 transgenic AD mice were subjected to 12 weeks of treadmill exercise, followed by spatial memory tests. After the behavioral study, the amyloid (Aβ) pathology, gut microbes and metabolites, bacterial lipopolysaccharide (LPS) displacement, and degree of neuroinflammation were analyzed. We found that this strategy of exercise enriched gut microbial diversity and alleviated neuroinflammation in the brain. Notably, exercise led to reductions in pathogenic bacteria such as intestinal Allobaculum, increases in probiotic bacteria such as Akkermansia, increased levels of intestine–brain barrier proteins, and attenuated LPS displacement. These results suggest that prolonged exercise can effectively modulate gut microbes and the intestinal barrier and thereby reduce LPS displacement and ultimately alleviate AD-related neuroinflammation.

Effects of Ten Different Exercise Interventions on Motor Function in Parkinson’s Disease Patients—A Network Meta-Analysis of Randomized Controlled Trials

Objective: The aim of this study was to evaluate ten exercise interventions (YOGA: yoga training, RT: resistance training, AQU: aquatic training, TAI: Taiji Qigong training, TRD: treadmill training, VR: virtual reality training, DANCE: musical dance training, WKT: walking training, CYC: cycling training, BDJ: Baduanjin Qigong training) on motor function in Parkinson’s disease (PD) patients. Design: Through searching PubMed, Embase, Cochrane Library, Web of Science, and CNKI, only randomized controlled trials (RCTs) were collected to study the effects of the ten exercise interventions on motor function in patients with Parkinson’s disease. The included studies were evaluated for methodological quality by the Cochrane bias risk assessment tool. Results: The RCTs were collected between the earliest available date and April 2022. Sixty RCTs were included and the total sample size used in the study was 2859. The results of the network meta-analysis showed that DANCE can significantly improve patients’ Berg Balance Scale (BBS) (SUCRA = 78.4%); DANCE can significantly decline patients’ Unified Parkinson’s Disease Rating Scale score (UPDRS) (SUCRA = 72.3%) and YOGA can significantly decline patients’ Timed-Up-and-Go score (TUGT) (SUCRA = 78.0%). Conclusion: Based on the network meta-analysis and SUCRA ranking, we can state that dance, yoga, virtual reality training and resistance training offers better advantages than other exercise interventions for patients’ motor function.