Q. What causes hot flashes in menopausal women? A. ‘It is truly amazing that although these feelings of intense heat, often followed by sweating, have been described in the medical literature since the 17th century, we still do not know the actual cause, said Dr. Lila E. Nachtigall, a professor of obstetrics and gynecology at the New York University School of Medicine and an expert on menopause. What is known, Dr. Nachtigall said, is that the flashes, also known as hot flushes, almost always occur as the estrogen production from the ovaries is decreasing or when estrogen is no longer produced at all. ‘Yet careful research has shown that the specific level of estrogen is not what causes flushes, she said, and estrogen levels do not differ between women who have severe flushes at menopause and women who have none. ‘What seems to make the difference, she said, ‘is the number of estrogen receptors in an area of the brain called the hypothalamus. When these receptors are not satisfied, they give off a substance that researchers are calling brain norepinephrine. This substance has not yet been isolated, but it seems to be similar to epinephrine made […]