The growth of the continental crust has shaped the evolution of the Earth from its interior to its fluid envelopes. Continents have played a major role in the evolution of global tectonics through their interaction with mantle convection. The feedback between continents and mantle convection has been studied for the past 25 years, but it is only recently that the dynamic influence of continents on seafloor spreading can be explored thanks to progress in convection modeling. In this work, we investigate how continental size impacts seafloor spreading activity with state-of-the-art three-dimensional spherical convection models. We show that increasing the continental area forces higher production rates of new seafloor with stronger fluctuations. As a consequence, the average age of the seafloor decreases with increasing continental area. This study suggests that mantle heat loss experienced significant fluctuations through continental growth and reinforces the estimate of <10% continental growth since the late Archean.