Early-stage Alzheimer?s disease: are skeletal muscle and exercise the key?

Alzheimer's disease (AD) is the most common form of dementia affecting approximately 6.5 million people in the United States alone. The development of AD progresses over a span of years to possibly decades before resulting in cognitive impairment and clinically diagnosed AD. The time leading up to a clinical diagnosis is known as the preclinical phase, a time in which recent literature has noted a more severe loss of body mass and more specifically lean muscle mass and strength prior to diagnosis. Mitochondria dysfunction in neurons is also closely associated with AD, and mitochondrial dysfunction has been seen to occur in skeletal muscle with mild cognitive impairment prior to AD manifestation. Evidence from animal models of AD suggests a close link among skeletal muscle mass, mitochondria function, and cognition. Exercise is a powerful stimulus for improving mito-chondria function and muscle health, and its benefits to cognition have been suggested as a possible therapeutic strategy for AD. However, evidence for beneficial effects of exercise in AD-afflicted populations and animal models has produced conflicting results. In this mini-review, we discuss these findings and highlight potential avenues for further investigation that may lead to the implementation of exercise as a therapeutic intervention to delay or prevent the development of AD.

Automated summary

Alzheimer's disease (AD) is the most common form of dementia, affecting approximately 6.5 million people in the US. The preclinical phase of AD is characterized by severe loss of body mass, particularly lean muscle mass and strength. Mitochondrial dysfunction in neurons and skeletal muscle has been observed in individuals with mild cognitive impairment prior to AD manifestation. Exercise has been suggested as a potential therapeutic strategy for AD due to its positive effects on mitochondria function and muscle health, but conflicting results have been found in studies involving AD patients and animal models. Further investigation is needed to explore the potential benefits of exercise in delaying or preventing the development of AD.