There’s compelling evidence that training with light loads can build muscle just as effectively as heavier loads when sets are taken sufficiently close to failure. However, some influencers claim that high-reps should be avoided because they induce substantial fatigue. It’s true that some acute research suggests greater strength impairment and perceived discomfort after light vs heavy load (e.g., PMID: 32401690). Why? High-rep sets produce substantial metabolic stress and acidosis, which can make training feel particularly demanding and associated neuromuscular effects conceivably may linger. However, there’s an important caveat: light-load training is unfamiliar to most lifters. Because novel exercise tends to produce greater muscle damage and fatigue, these acute findings may overstate the recovery demands of light-load training when performed regularly. Indeed, repeated exposure ultimately attenuates these effects. To this point, our lab conducted an 8-week study examining the effects of light (25–35RM) versus heavier (8–12RM) loads performed to failure in trained men (PMID: 25853914). During the first week, several participants in the light-load group puked, and all reported high levels of discomfort. By the second week, however, these adverse responses had largely resolved. Importantly, the overwhelming body of longitudinal research shows similar whole muscle hypertrophy with light vs heavy load training, indicating that fatigue does not influence results. From a practical standpoint, using a range of loading zones may be a viable approach to maximize hypertrophy while providing variety in training. Also, some research shows that different loads may preferentially stimulate different muscle fiber types, which could be synergistic to hypertrophy (evidence remains equivocal). Take-home: Acute research cannot necessarily be extrapolated to long-term results. Light loads are an effective hypertrophy stimulus—but “lighter” doesn’t necessarily mean “easier.” High-rep sets near failure can be extremely demanding and may temporarily prolong recovery, but evidence indicates any initial effects on fatigue don’t compromise long-term gains.