Background: Human sexual activity serves both reproductive and pleasurable purposes. Many individuals engage in solitary sexual practices that are often linked to pornography. The psychological and physiological aspects of sexual arousal and masturbation have been explored in the literature, revealing divergent findings, particularly regarding cardiovascular, endocrine, and neurological responses. This study sought to enhance our understanding of these responses in the context of sexual arousal and masturbation in humans.
Methods: We conducted a systematic review of clinical trials, cohort, case-control, and cross-sectional studies, and excluded case reports, case series, short communications, conference papers, letters to editors, in vitro research, animal studies, and correspondence. We searched five medical databases (PubMed, Embase, PsycInfo, Web of Science, and Scopus) using specified keywords and extracted data on the baseline population, study details, gender proportions, sexual arousal/masturbation data, study objectives, findings, and endpoints. The analysis was performed using a sex-specific approach.
Results: During pornography-induced sexual arousal, blood pressure and heart rate increased in both sexes, although the male heart rate varied. Female vaginal blood volume and male genital blood flow increase with elevated Vaginal Pulse Amplitude (VPA). LH levels increased in men, whereas FSH levels remained stable. Pornography increased FSH levels in men, while PRL concentrations decreased in women, but remained unchanged in men. Vasopressin levels remained unaffected in the men. Female sexual stimulation raises estradiol levels, and cortisol levels decrease only slightly in both sexes. Testosterone and adrenaline levels may also increase during pornography.
In terms of brain activity, the right hemisphere shows increased activity in females, while right-handed males exhibit broad stimulation in various brain regions. Masturbation increases the heart rate and blood pressure of men, peaking during orgasm, whereas VPA significantly increases these parameters. Hormone responses varied during the masturbation. Prolactin levels peaked in males during orgasm, vasopressin remained unchanged, and cortisol levels did not change. The testosterone and adrenaline levels may also increase. Female masturbation affects testosterone and progesterone levels, and increases adrenaline levels. Oxytocin changes during male orgasm.
Conclusion: Most studies have demonstrated a correlation between sexual arousal induced by pornography or masturbation, and the response levels of different physiological systems. However, our systematic literature search revealed inconsistencies in certain of the observed physiological changes. More experimental studies and analyses are needed to define precise responses during and after masturbation.