From Encyclopedia of Sex and Sexuality
An acute and common symptom of menopause. Also known as flushes, they are characterized by a sudden feeling of intense heat, followed by a flushing of the upper body, profuse sweating, and often heart palpitations. A sensation of pressure in the head may mark the beginning of a flash. The actual feeling of warmth or burning is centered in the face, neck, upper chest, and back; it is sometimes accompanied by patchy flushing of the skin and an outburst of sweating follows immediately. Both the feeling of heat and sweating subsequently spread all over the body. Vertigo, lightheadedness, fatigue, nausea, and headache are some of the less frequent symptoms accompanying flashes. The flash typically ends in a cold shiver.
Hot flashes are disturbing and uncomfortable; the feeling of heat forces most women to fan themselves, move off bed covers, shed clothing, or open the window. Since flushes are more common at night, they are commonly known as “night sweats.” Women usually wake up from the discomfort, and consequently may suffer from insomnia, drowsiness, or inattentiveness.
The average length of a flush is about four minutes, although it varies from a few seconds to ten minutes. Some women experience a flush as often as once or twice an hour, whereas others have it once or twice a week. During the year after their last menstrual period, 75 percent of women experience hot flashes. Among these women, 82 percent will have symptoms for more than a year, and 25 to 85 percent will continue to have repeated episodes of flushes for more than five years. Few women complain about this ten years after menopause.
The subjective feeling of hot flashes is associated with physiological changes, such as an increase of skin temperature and a decrease of the body’s core temperature. These changes occur just before the actual hot flash and disappear several minutes afterwards. Since both women in natural menopause and women who have had their ovaries removed (surgical menopause) suffer from hot flashes, scientists believe that lowered female sex hormones are responsible for their occurrence. Body temperature is controlled by regulatory centers in the brain that operate like a thermostat with a certain temperature set point. Both natural and surgical menopause lead to a reduction of estrogen, which triggers a severe drop of the thermoregulatory set point. Mechanisms that induce heat loss, such as sweating and flushing, bring the core temperature to the level of the new set point.
Since hot flashes are most likely the result of estrogen withdrawal, the most common and effective treatment is estrogen replacement. This reduces hot flashes and generally improves sleep. However, although estrogen provides temporary relief, it is not a cure, and symptoms will return without continued treatment.
Other drugs have also been used to relieve the symptoms of hot flashes. Progestins such as depomedroxyprogesterone acetate (Depo-Provera), the second most commonly used therapy, are prescribed for patients who cannot take estrogens. Clonidine (Catapres), an antihypertension drug, is relatively effective in relieving the symptoms. It is often used in hypertensive women, since they have a better tolerance of its side effects. Other agents, such as tranquilizers, sedatives, and antidepressants, along with vitamins E and K, belladonna alkaloids, and mineral supplements have been tried; their efficiency is not clearly known. Because of the potential for addiction and drug-related side effects, they are not usually prescribed for the treatment of hot flashes (see also Hormone Replacement Therapy).