To make green hydrogen more economically attractive, the energy losses in alkaline electrolysis need to be minimized while operating at high current densities (1 A cm⁻²). At these current densities the ohmic resistance and gas bubbles effects contribute largely to the energy losses. To mitigate the gas bubbles losses, we demonstrate, for the first time, a pressure swing to remove gas bubbles in a zero-gap alkaline water electrolyzer. The pressure swing leverages the ideal gas law to increase the volume of gas in the system periodically, for a short duration (<2 s). This temporal volume increase effectively removes bubbles from the electrolyzer. We show that pressure swing can be used to measure the effect of bubbles on the ohmic resistance (R_Bubbles). Our results reveal that foam electrodes have a significantly larger R_Bubbles than perforated plate electrodes (1.8 Ω cm² vs 0.3 Ω cm²). The time-averaged cell voltage reduces by 170 mV when applying pressure swings to an electrolyzer operating at 200 mA cm⁻² in 1 M KOH with foam electrodes. The bubble resistance further depends on the electrolyte conductivity (inversely proportional) and is only moderately affected by operating pressure (25 % lower when increasing pressure amplitude from 1–2 to 1–5 bar). By implementing these findings in a model, we estimate that the pressure swing could reduce the cell voltage by ∼0.1 V for an electrolyzer operating at industrial conditions (6 M KOH, 80 °C, 1 A cm⁻²) for foam electrodes. For perforated plate electrodes, however, the reduced cell voltage is lower and does not outweigh the additional compression energy.