EFEITOS NEUROPROTETORES DO EXERCÍCIO FÍSICO SOBRE A DOENÇA DE ALZHEIMER: UMA REVISÃO DE LITERATURA

Abstract

Alzheimer's disease (AD) affects more than 55 million people and could triple by 2050. This integrative review, based on the PICO strategy, analyzed 20 high-level evidence studies published between 2021 and 2025, aiming to assess whether regular physical exercise can slow the progression of AD in pre-clinical and early stages. Results were consistent: in older adults with elevated β-amyloid, greater objectively measured physical activity (accelerometers/pedometers) significantly reduces cognitive and functional decline. The main mechanism is not the decrease in amyloid load, but the reduction in the accumulation of hyperphosphorylated tau in the inferior temporal cortex – a central stage of neurodegeneration and the main mediator of the observed protection. The dose-response relationship is curvilinear, with maximum benefit between 5,001 and 7,500 daily steps (a realistic target even for sedentary individuals), with a plateau occurring above that. In parallel, exercise combats sarcopenia, breaking the vicious cycle between muscle loss, chronic inflammation, insulin resistance, and accelerated AD. Regular programs (≥3 sessions/week, moderate-to-vigorous intensity) increase BDNF, cathepsin B, and humanin, reduce neuroinflammation, and improve mitochondrial function. Conclusion: physical exercise is currently the most effective, safe, and accessible non-pharmacological intervention to modify the trajectory of early AD, especially by slowing tauopathy and sarcopenia. Its early and supervised prescription in sedentary individuals with positive biomarkers is no longer optional but has become a clinical and ethical imperative.

Keywords: Alzheimer's disease; physical exercise; sarcopenia; treatment.