While ferroelectric HfO₂ shows promise for use in memory technologies, limited endurance is one factor that challenges its widespread application. In this study, endurance is investigated through field cycling W/Hf_0.5Zr_0.5O₂/W capacitors above the coercive field while manipulating the time-under-field using bipolar pulses of varying pulse duration or duty cycle. Both remanent polarization and leakage current increased with increasing pulse duration. Additionally, an order of magnitude decrease in the pulse duration from 20 to 2 μs resulted in an increase in endurance lifetime of nearly two orders of magnitude from 3×10⁶ to 2×10⁸ cycles. These behaviors are attributed to increasing time-under–field allowing for charged oxygen vacancy migration, initially unpinning domains, or driving phase transformations before segregating to grain boundaries and electrode interfaces. This oxygen vacancy migration causes increasing polarization before creating conducting percolation paths that result in degradation and premature device failure. This process is suppressed for 2 µs pulse duration field cycling where minimal wake-up and lower leakage before device failure is observed, suggesting that very short pulses can be used to significantly increase device endurance. These results provide insight into the impact of pulse duration on device performance and highlight consideration of use conditions when endurance testing.