Chronic paraquat exposure at 10-20 mM concentrations accelerated functional decline in fruit flies, with behavioral half-life dropping 48-53% at the highest dose. Female flies maintained superior climbing performance under moderate stress (10 mM) but lost this advantage under severe oxidative pressure (20 mM). The strong correlation between motor function and survival (r = 0.87) demonstrates that climbing ability serves as a reliable predictor of overall healthspan. This Drosophila research illuminates fundamental mechanisms underlying sex differences in aging resilience. The female protective advantage against oxidative damage, observed across species from flies to humans, likely stems from enhanced antioxidant systems and mitochondrial efficiency. However, these protective mechanisms appear to have thresholds beyond which they become overwhelmed. The compressed interval between functional decline and death under severe stress mirrors patterns seen in human neurodegenerative diseases, where motor symptoms often precede mortality by years under normal aging but accelerate dramatically under pathological conditions. While fly studies cannot directly translate to human aging timescales, the consistent sex-specific responses to oxidative stress suggest conserved biological mechanisms. This work reinforces climbing performance as a valuable biomarker for neuromuscular health assessment in aging research.