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In men, sexual dysfunction refers to difficulties engaging in sexual intercourse. Sexual dysfunction encompasses a variety of disorders that affect sex drive (libido), the ability to achieve or maintain an erection (erectile dysfunction, or impotence), ejaculation, and the ability to achieve orgasm.

Sexual dysfunction may result from either physical or psychologic factors. Many sexual problems result from a combination of physical and psychologic factors. A physical problem may lead to psychologic problems (such as anxiety, fear, or stress), which can in turn aggravate the physical problem. Men sometimes pressure themselves or feel pressured by a partner to perform well sexually and become distressed when they cannot (performance anxiety). Performance anxiety can be troublesome and further worsen a man's ability to enjoy sexual relations.

Did You Know... Sexual dysfunction may affect the sex drive or the ability to have an erection, to ejaculate, or to have an orgasm. How much of sexual dysfunction is due to physical factors and how much is due to psychologic factors can be difficult or impossible to discern.

Erectile dysfunction is the most common sexual dysfunction in men. Decreased libido also affects some men. Problems with ejaculation include uncontrolled ejaculation before or shortly after penetrating the vagina (premature ejaculation), ejaculation into the bladder (retrograde ejaculation), and inability to ejaculate (anejaculation).

Psychologic Causes of Sexual Dysfunction Anger toward a partner Anxiety Depression Discord or boredom with a partner Fear of pregnancy, dependence on another person, or losing control Feelings of detachment from sexual activities or one's partner Guilt Inhibitions or ignorance about sexual behavior Performance anxiety (worrying about performance during intercourse) Previous traumatic sexual experiences (for example, rape, incest, sexual abuse, or previous sexual dysfunction)

Normal Sexual Function

Normal sexual function is a complex interaction involving both the mind (thoughts, memories, and emotions) and the body. The nervous, circulatory, and endocrine (hormonal) systems all interact with the mind to produce a sexual response. A delicate and balanced interplay among all parts of the nervous system controls the sexual response in men.

Desire (also called sex drive or libido) is the wish to engage in sexual activity. It may be triggered by thoughts, words, sights, smell, or touch. Desire leads to the first stage of the sexual response cycle, excitement. Excitement is sexual arousal. During excitement, the brain sends nerve signals through the spinal cord to the penis. The arteries supplying blood to the erectile tissues (corpora cavernosa and corpus spongiosum) respond by widening (dilating). The widened arteries dramatically increase blood flow to these areas, which become engorged with blood and expand. Muscles tighten around the veins that normally drain blood from the penis, slowing the outflow of blood and elevating blood pressure in the penis. This elevated blood pressure causes the penis to increase in length and diameter, producing an erection. Also, muscle tension increases throughout the body.

In the plateau stage, excitement and muscle tension are maintained or intensified. Orgasm is the peak or climax of sexual excitement. At orgasm, muscle tension throughout the body further increases. The man experiences contractions of the pelvic muscles followed by a release of muscle tension. Semen is usually, but not always, ejaculated from the penis. Ejaculation results when nerves stimulate muscle contractions in the male reproductive organs such as the seminal vesicles, prostate, and the ducts of the epididymis and vas deferens. These contractions force semen into the urethra. Contraction of the muscles around the urethra further propels the semen through and out of the penis. The neck of the bladder also constricts to keep semen from flowing backward into the bladder.

Although ejaculation and orgasm often occur nearly simultaneously, they are separate events. Ejaculation can occur without orgasm. Also, orgasm can occur in the absence of ejaculation, especially before puberty, or with the use of certain drugs (such as some antidepressants) or after surgery (such as removal of the prostate gland). Most men find orgasm highly pleasurable.

In resolution, a man returns to an unaroused state. Once ejaculation takes place or orgasm occurs, penile arteries constrict and the veins relax, reducing blood inflow, increasing blood outflow and causing the penis to become limp (detumescence). After orgasm, erection cannot be obtained for a period of time (refractory period), often as short as 20 minutes or less in young men but longer in older men. The time between erections generally increases as men age.

Sexual Activity and Heart Disease Sexual activity is generally less taxing than moderate to heavy physical activity and is therefore usually safe for men with heart disease. Although the risk of a heart attack is higher during sexual activity than it is during rest, the risk is still very low during sexual activity. Still, sexually active men with diseases of the heart and cardiovascular system (which include angina, high blood pressure, heart failure, abnormal rhythms of the heart, and blockage of the aortic valve [aortic stenosis]) need to consult their doctor. Usually, sexual activity is safe if the disease is mild, if it causes few symptoms, and if blood pressure is normal. If the disease is moderate in severity or if the man has other conditions that make a heart attack likely, testing may be necessary to determine how safe sexual activity is. If the disease is severe or if the man has an enlarged heart that blocks the flow of blood leaving the left ventricle (obstructive cardiomyopathy), sexual activity should be deferred until after treatment reduces the severity of the symptoms. Sexual activity should also be deferred until at least 2 to 6 weeks after a heart attack. Use of sildenafilSome Trade Names VIAGRA , vardenafil, and tadalafil may be dangerous in men taking nitroglycerinSome Trade Names NITRO-BID NITROL , who should not use these drugs. Most often, testing to determine the safety of sexual activity involves monitoring the heart for signs of poor blood supply while the man is exercising on a treadmill. If the blood supply is adequate during exercise, a heart attack during sexual activity is very unlikely.

Last full review/revision September 2007 by Fran E. Kaiser, MD