Alzheimer’s disease (AD) is one of the most common causes of dementia, affecting millions worldwide. As the population ages, the prevalence of AD is expected to rise dramatically, from 50 million people in 2010 to an estimated 113 million by 2050. Given the growing concern, researchers are constantly exploring innovative ways to manage and mitigate the effects of this neurodegenerative disease. One promising approach is the incorporation of physical exercise (PE) as a non-pharmacological intervention.

The Power of Physical Exercise

Physical exercise has long been recognized for its myriad health benefits, from enhancing cardiovascular health to boosting mental well-being. However, its potential role in reducing chronic inflammation and improving cognitive health is garnering significant attention. The connection between physical activity and brain health is complex and multifaceted, involving the immune system, gut microbiota, and neuroinflammation.

The Gut–Brain Axis: A Vital Link

One of the critical aspects of how PE impacts brain health is through the gut–brain axis. This bi-directional communication pathway highlights the role of gut microbiota (GM) in maintaining brain health and preventing neurodegenerative diseases. Exercise has been shown to positively influence the composition and diversity of gut microbiota, which in turn can alleviate neurological symptoms. This interaction between the gut and muscle—where gut microbiota diversity affects muscle metabolism and muscle activity influences gut microbiota—can significantly modulate cognitive functions.

Irisin and BDNF: The Exercise-Induced Duo

A fascinating element in this interplay is irisin, a myokine produced by muscles during exercise. Irisin has been found to promote neuroplasticity and cognitive function through brain-derived neurotrophic factor (BDNF) signaling. This mechanism suggests that the benefits of physical activity against Alzheimer’s disease might be mediated by the interaction of exercise with the gut microbial ecosystem, neural plasticity, anti-inflammatory pathways, and neurogenesis.

Understanding Alzheimer’s Disease and Its Symptoms

Alzheimer’s disease is characterized by the accumulation of Tau protein and amyloid-β (Aβ) peptides in the brain, leading to neurofibrillary tangles and amyloid plaques. This accumulation disrupts synaptic homeostasis, leading to cognitive impairments and neuropsychiatric symptoms (NPSs) such as depression, apathy, aggression, and psychosis. These symptoms not only deteriorate the patient’s quality of life but also pose a significant burden on caregivers.

The Role of Neuropsychiatric Symptoms

NPSs are not only common in AD patients but are also indicators of disease progression. Symptoms like depression and apathy can precede cognitive decline, suggesting their potential as early markers for rapid disease progression. Aggression and agitation, on the other hand, are linked to emotional distress and impaired social functioning, further complicating the management of AD.

Physical Exercise as a Therapeutic Tool

Given the limitations of current pharmacological treatments, which mainly focus on symptom management, incorporating physical exercise into the treatment regime offers a holistic approach. By improving gut microbiota diversity and promoting neuroplasticity through mechanisms involving irisin and BDNF, exercise can potentially modify the disease trajectory.

In conclusion, the integration of physical exercise into daily routines holds promise not only for enhancing overall health but also for combating the progression of Alzheimer’s disease. Understanding the gut–muscle–brain connection can pave the way for innovative strategies to promote brain health, fight cognitive decline, and improve the quality of life for those affected by AD.

References

Cutuli, D., Decandia, D., Giacovazzo, G., & Coccurello, R. (2023). Physical exercise as disease-modifying alternative against Alzheimer’s disease: A gut–muscle–brain partnership. International Journal of Molecular Sciences, 24, 14686.