In the last decades, the resistance to high-power laser flux was largely improved in most of optical components insofar as 1-on-1 measurements are concerned. Another challenge lies in improving their resistance to multiple laser shots for highpower laser applications. Indeed, in multi-pulse irradiation, a decrease of the laser-induced damage threshold with increasing number of pulse was observed in various optical materials as in glasses, crystals, and thin-films. This effect, commonly denominated "fatigue" effect, is a limiting factor in many applications where optics have to be long-lifetime, as for example for space applications. Representing the laser damage probability as a function of pulse number for a given fluence allows to distinguish statistical pseudo-fatigue and fatigue which is due to cumulative material modifications. Investigating on the fatigue effects in the bulk of synthetic fused silica (Suprasil 1®) for different wavelengths, we evidenced that the fatigue effect was due to statistical pseudo-fatigue when irradiated at 1064 nm while the fatigue effect at 355 nm came from cumulative material modifications. The current work is dedicated a more detailed study of fatigue effects in Suprasil 1®, testing the influence of the beam size on the fatigue effects. Moreover, an estimation of the lifetime of the created defects is performed using a destructive technique.