This study replicated initial findings of positive effects of acute vigorous-intensity aerobic exercise on worry, state anxiety, and feelings of energy and fatigue among young adult women with analogue GAD, examined responses among young adult men with analogue GAD, and explored sex-related differences and moderation by physical activity level, trait anxiety, depression, and poor sleep status. Thirty-five young adults (21.4 ± 2.3 yr; 19 males; 16 females) with Penn State Worry Questionnaire scores ≥45 (60 ± 8) completed two counterbalanced 30-min conditions: treadmill running at ~71.2% ± 0.04% HR reserve and seated quiet rest. Outcomes included worry, worry engagement, absence of worry, state anxiety, and feelings of energy and fatigue. No outcome or moderator differed at baseline between sexes. Exercise significantly improved state anxiety (P < 0.04; d = 0.27) and feelings of energy (P < 0.001; d = 1.09). Small nonsignificant improvements were found for worry (d = 0.22), worry engagement (d = 0.18), and feelings of fatigue (d = 0.21). The magnitude of improvements in worry, worry engagement, absence of worry, and feelings of energy were stronger among females. Significant large, potentially clinically meaningful increases in feelings of energy were found among women (d = 1.35) and men (d = 0.92). A nonsignificant, but potentially clinically meaningful, moderate reduction in worry (d = 0.53) was found among women. High-trait anxiety and poor sleep quality were supported as moderators. Findings replicated positive effects of acute aerobic exercise among young adult women with analogue GAD, and extended to support for positive effects among young adult men with analogue GAD.