Does Rest Days actually make a difference, or is it overhyped?

There is no direct meta-analytic literature under the label "rest days," but the closely related question of optimal resistance-training frequency has been studied extensively: multiple meta-analyses find that training a muscle group roughly twice per week produces greater hypertrophy than once weekly, provided total weekly volume is matched, implying that adequate spacing (i. Weighing the data: Rest Days looks an early-stage, lower-priority area for now — the evidence is only moderate (58/100), and its estimated impact (35/100) is on the lower end too.