Night Sweats and Hot Flashes - Who Gets Them and When?

Night sweats and hot flashes are by far the most common complaint of menopause. They begin in perimenopause (before menstrual periods stop) and continue after. When they start and how long they last, what they are like and how bad they are, varies greatly among women.

Night sweats are hot flashes which occur at night. A hot flash begins with the sensation of heat followed by perspiration to intense sweating in the area of the heat. At night one tends to awake after the wave of heat to experience the aftermath of the flash, which is the sweating.

Hot flashes (HF) are often one of the first signs that you are entering perimenopause. This is the time period when your ovaries are beginning to shut down their production of progesterone and estrogen. Eventually the ovaries produce so little of these sex hormones that they stop releasing eggs and your menstrual cycle stops all together.

Menopause is the point in time when you have your last menstrual cycle. Here are some statistics on when menopause (and hot flashes/night sweats) starts and how long it lasts:

• The age range for menopause is 40 to 58 years.


• In Western countries the median age is 51.


• HF are a complaint for 80% of women in Western countries.


• 30% of women report HF that are so severe and frequent that they are a major disruption of their lives.


• Yet only 10% to 15% of women consult a physician in an attempt to alleviate their HF.


• The average age of onset of night sweats and HF is 46, but onset has been reported as early as age 35.

Perimenopause averages 5 years for most women. Remember that for the women who will experience them, hot flashes typically start at the onset of perimenopause when sex hormone production in the ovaries begins to drop. Again, the average age of onset of perimenopause is ages 46, but there are reports of women entering perimenopause as young as 35.

Starting at the beginning of perimenopause, hot flashes often occur just before and during the menstrual cycle. When they occur at the end of the cycle it means that estrogen levels are low, but not low enough to cause cessation of the monthly cycle. As time passes and ovarian hormones continue to drop they generally increase in frequency and intensity, occurring throughout the month.

The intensity and frequency of hot flashes accelerates during the two years before the last menstrual cycle. They are usually the most severe during the two years following the last menstrual cycle (menopause).

Hot flashes (HF's) continue after menopause for an average of 5 years, but approximately 10% of women experience them for as long as 10 years after menopause. For the women in Western countries who experience them, 85% of women experience them for more than one year, and 20-50% experience them for a total of more than 5 years.

The percentage of women who experience HF's varies widely in different cultures, from as little as 25% to as great as 85%. For instance in Japan women report experiencing HF's much less frequently than do women in Western cultures. One possible reason for this is the high soy content of the Japanese diet, containing plant estrogens (phytoestrogens).

Hot flashes are a sign of dropping hormone levels. Disruption of hormone levels can occur at other times in life, causing them before perimenopause. Up to two thirds of women may also experience occasional them even before perimenopause (during premenopause). A common time is immediately after childbirth.

Hot flashes (HF's) are experienced in over 90% of women who suffer an unnatural menopause (with both ovaries removed). The term "induced menopause" is used to describe whenever the ovaries are forced to shut down production of the sex hormones artificially. This can be due to surgical removal of the ovaries in a total hysterectomy, or as a result of radiation therapy as part of cancer treatment.

There are a number of remedies for relieving HF's and night sweats. These include hormone replacement therapy, herbal remedies, changes in diet, not over dressing, stress management and more.

Many women shy away from hormone replacement therapy (HRT) because of the associated increased risk for breast cancer and cardiovascular disease. Other risks associated with HRT include bleeding, nausea and vomiting, altered mood, breast tenderness, headache, weight change, dizziness, venous thromboembolic events (blood clots), rash, pruritis (itching), cholecystitis (gall bladder inflammation), and liver problems.

Many women try herbal remedies instead. But most of these fall far short of the relief provided by HRT. Studies show that HRT reduces hot flashes by 75%.

An herbal solution that has only recently become available in the United States has been well researched in Europe. This herb, Siberian rhubarb root extract has been used in Germany for hot flashes since 1993 and shown have no significant side effects in women who have taken it for two years.