Patterns of female sexual arousal during sleep and waking: Vaginal thermo-conductance studies

Abstract

The main objective of this investigation was to ascertain whether there are, in the female, periods of sexual excitation or arousal during REM sleep similar to the cycle of penile erections in the male. In a group of 10 subjects, 21–35, utilizing a thermoconductance method that gives a measure of vaginal blood flow (VBF), we are able to confirm that females manifest cyclic episodes of vascular engorgement during REMPs equivalent to erections in men. They occur with equal frequency (95% of REMPs) but differ in distribution, in greater frequency during NREM sleep, in the shorter duration of individual VBF episodes, and in the less tight linkage of VBF episodes to the REMPs. The increases in VBF, in terms of rises of the recording pen on the graph paper, varied from 10 to 45 mm. In order to ascertain the significance of these increases, we compared these sleep responses with waking VBF responses evoked by nonerotic and erotic stimuli and by masturbation. Only erotic stimuli gave VBF responses, the greatest to the movie and masturbation; these were no greater than the maximum levels attained during sleep, namely 40 to 45 mm. Maximum vascular engorgement is finite in male and female and is limited by anatomy. The fact that VBF REM increases appear to be identical to VBF responses to passive waking erotic stimulation and show similar cardiorespiratory patterns suggests that they, too, are erotic in nature. Additionally, the preliminary results of the waking experiment demonstrate that a very high percentage of VBF REM increases are associated with dreams that contain overt or symbolic sexual content. The results indicate that REM periods with VBF increases have a far greater chance of being associated with sexual dreams than do REMPs or NREMPs with minimal VBF increases.