The roles of testosterone and alpha-amylase in exercise-induced sexual arousal in women

Introduction. Several studies have demonstrated that moderate exercise increases genital response to erotic stimuli in women. The increase in genital arousal could be the result of various changes that can occur in response to exercise including changes in hormone levels, neurotransmitter levels, mood, and autonomic nervous system activity. Aim. The present study was an attempt to shed light on two such mechanisms through which exercise enhances sexual arousal. Methods. Sixteen participants came into the lab on two separate occasions: during one visit, they filled out questionnaires for 20 minutes, and during the other visit, they exercised on a treadmill for 20 minutes. The questionnaires and exercise were both followed by the presentation of a neutral then erotic film during which the women's physiological sexual arousal was measured. Saliva samples were taken at baseline, prefilm, and postfilm. Main Outcome Measures. Subjective arousal was measured using a self-report questionnaire, and genital arousal was measured by a vaginal photoplethysmograph. Testosterone and alpha-amylase (a marker of sympathetic nervous system [SNS] activity) were measured via saliva assays. Results. Findings replicated previous studies showing a significant increase in physiological sexual arousal with exercise. There was a significant increase in alpha-amylase across the study in the exercise condition, but not in the no-exercise condition. There were no differences in testosterone levels between the exercise and no-exercise conditions. Conclusions. SNS activity is one mechanism through which exercise increases genital sexual arousal. Testosterone does not mediate the relationship between exercise and genital sexual arousal. Hamilton LD, Fogle EA, and Meston CM. The roles of testosterone and alpha-amylase in exercise-induced sexual arousal in women. J Sex Med 2008;5:845-853.