Vasocongestion

Vasocongestion is a term for the swelling of bodily tissues caused by increased vascular blood flow and a localized increase in blood pressure. Typical causes of vasocongestion in humans includes menstruation, sexual arousal, REM sleep, strong emotions, and illnesses and allergic reactions.

Female vasocongestion

Menstrual cramps are one of the most common side effects of vasocongestion in adult females. Although pain and discomfort varies among individuals, vasocongestion is an essential part of the shedding of the lining of the uterus. Abnormal vasocongestion during the menstrual cycle can lead to irregular bleeding, severe and debilitating cramps and anemia caused by increased menstrual flow.

The temporary vasocongestion of the cheeks of the face is called blushing. It may be caused by the emotions of anger or embarrassment. The illness of rosacea is a chronic vasocongestion condition of the face that primarily affects the cheeks and nose, but may include other areas such as the eyes and chin.

Vasocongestion of the area around the human anus can lead to the formation of hemorrhoids.

Sexual arousal

Sexual arousal causes increased pelvic blood flow, genital vasocongestion, vaginal dilatation and lengthening, engorgement of the labia minora and tissue surrounding the urethral lumen, clitoris and vestibular bulbs. Sites of genital sensory activation include the clitoris, clitoral sheath, anterior vaginal wall, labial and introital area, urethra, Halban’s fascia between the anterior vaginal wall and bladder, and the controversially discussed G-spot, an anterior vaginal wall area along the urethra.

Vasocongestion is essential for sexual procreation in mammals since this is the force that causes the hardening of a penis during an erection. The same force in woman leads to the hardening of the clitoris and vaginal lubrication during sexual arousal. The decrease in vasocongestion in post-menopausal women may require some women to use artificial sexual lubricant to avoid pain during sexual intercourse.

Other forms of vasocongestion during human sexual activity include sex flush and the swelling of nipples in both men and women.

Unpleasant side effects of sex-related vasocongestion may lead to the cramp-like pain of “blue balls” in males and an unpleasant pelvic “heaviness” in women, similar to the start of the menstruation cycle.

Female orgasm

There is considerable evidence that female genital organs, including the clitoris, vagina and uterus become vasocongested during sexual arousal and remain that way during and following orgasm. This reduces blood flow in some veins and prevents blood flowing out of the genital organs. Pressure and swelling in the tissues surrounding the genitals as well as contractions of genital muscles also reduce blood flow in the genital region, increasing vasocongestion.

Muscle activation

The uterus and a number of pelvic muscle groups become active during sexual arousal and orgasm. These muscle groups include:

• The muscles which surround the opening of the vagina and exert pressure on the clitoris,
• The muscles which support the perineum (the tissues between the anus and the genitals) during orgasm;
• The muscles which support what is known as the pelvic diaphragm, or the area of vaginal muscle inside the vagina which typically undergoes spontaneous contractions during orgasm.

Smooth muscle contractions

The primary physical indicator of orgasm is contractions of the genito-pelvic and/or anal muscles. When these contractions were first observed in women experiencing orgasm, it was found they occurred at 0.8 second intervals and lasted on average for 16.7 seconds (compared to 25 seconds for men). It is however unclear whether or not all women experience vaginal muscle contractions during orgasm. It is also unclear if the commencement and cessation of such contractions signal the beginning and end points of a female’s orgasm, or if such contractions simply occur close to the time of orgasm.

Changes to other body systems induced by the female orgasm

There is now considerable evidence that orgasm induces whole body, and not just genito-pelvic, changes. There is particularly good evidence regarding cardiovascular changes which occur during orgasm, including tachycardia (increased heart rate) and increased blood pressure. For example one study, in which the heart rate and blood pressure of ten women who watched pornography and masturbated to induce orgasm were compared to those of women who watched a documentary film, reported that heart rate and blood pressure of the masturbating women were higher than the documentary film watchers by the time they reached orgasm. Other studies have also noted bodily reactions to orgasm including shuddering, muscle spasms, rigidity, sweating, rocking pelvic motions, facial grimacing and abdominal muscle contractions.

Organs also cause changes in the central nervous system responses.

Hormonal changes in females caused by orgasm

A woman’s hormone profile (the relative concentrations of different types of hormones in her body) changes distinctly during orgasm. Similar to the hormonal changes which accompany male orgasm, the key hormone change associated with the female orgasm is a substantial increase in levels of a hormone called prolactin. There are however many other subtle hormone changes which women experience during orgasm including changes to the hormones testosterone, cortisol, estrogen, progesterone and plasma epinephrine (adrenaline).

Changes in the brain induced by orgasm

The brain is also an important source of sexual arousal and orgasm in women. There is evidence that individuals can experience orgasm with no direct stimulation to the genitals. This evidence comes from the orgasms experienced by paraplegics, from orgasms induced hypnotically, from orgasms stimulated by fantasy alone, and from orgasms experienced as a result of stimulation in certain areas of the brain. In addition, there have been reports of orgasm from women who have had a clitoral and labial excision and vaginal reconstruction. This research suggests that the brain be considered as part of the anatomical requirements for orgasmic experience.

It has also been proposed that several different nerve pathways are involved in sexual response:

• the pudendal nerve for clitoral stimulation;
• the hypogastric plexis and pelvic nerve for vaginal stimulation; and
• possibly the vagus nerve directly from the cervix to the brain.

Psychological changes in orgasm

The psychological changes associated with orgasm are measured subjectively, using rating scales. Women typically report feelings of ecstasy during orgasm and feelings of relaxation following orgasm.