Sex-Related Differences in Mood Responses to Acute Aerobic Exercise.

UNLABELLED Although some evidence supports stronger mood improvements in response to acute exercise among women, sex-related differences remain understudied. PURPOSE This study aimed to quantify and compare differences in baseline mood and the magnitude of mood responses to either acute aerobic exercise or quiet rest among young adult men and women. METHODS Fifty-three young adults (27 males and 26 females) completed two counterbalanced conditions: 30 min of vigorous treadmill exercise or 30 min of quiet rest. Outcomes included state anxiety, worry symptoms, and feelings of tension, depression, vigor, fatigue, anger, and confusion. ANOVA and RM-ANOVA examined sex-related differences at baseline and across condition and time, respectively. Hedges' d (95% CI) values were calculated to quantify and compare the magnitude of change in response to exercise compared with control. RESULTS Females were more likely to report scores indicative of depression (Quick Inventory of Depressive Symptoms > 5; 38.5% vs 18.5%) and high trait anxiety (≥1 SD above age- and sex-related norm on the trait subscale of the State-Trait Anxiety Inventory; 26.9% vs 3.7%). Baseline worry symptoms and trait anxiety were significantly higher among females (P < 0.02). Although repeated-measures models did not support statistically significant differences between sexes, the magnitude of improvement in mood outcomes was larger among females than males for all outcomes other than feelings of tension. Compared with quiet rest, exercise significantly improved feelings of fatigue (d = 0.59, 95% CI = 0.01-1.17), confusion (d = 0.83, 95% CI = 0.24-1.41), and energy (d = 1.67, 95% CI = 1.02-2.33), and total mood disturbance (d = 1.09, 95% CI = 0.49-1.70) and resulted in a nonsignificant, moderate-sized improvement in state anxiety (d = 0.51, 95% CI = -0.07 to 1.08) among females. CONCLUSION Findings support potential sex-related differences in mood response to acute aerobic exercise, with larger improvements found among females. Future research should confirm findings and examine putative mechanisms of sex-related differences in mood responses to exercise.