A hot flash is characterized by a sudden rush of heat, typically from a woman’s chest to her head. Hot flashes can range from a mild feeling of warmth to an even, intense heat in the body. Hot flashes are most often a symptom of menopause and in some cases, they can be accompanied by:

• Flushed appearance
• Red, blotchy skin on the face, arms and neck
• A rapid heartbeat
• Mild to drenching perspiration
• A chilled feeling after the hot flashes pass

When hot flashes occur at night while a woman is sleeping, they are referred to as night sweats. As estrogen levels decline during menopause, many women experience varying degrees of symptoms, including hot flashes. Hot flashes are the most common symptom of menopause. In fact, according to the Food and Drug Administration (FDA), about 85 percent of women approaching or going through menopause have hot flashes.

Hot flashes can be upsetting and frustrating for a woman, particularly if they are intense. However, menopausal symptoms are not a sign of a medical problem, but rather a normal biological reaction to fluctuating hormone levels within a woman’s body.

Menopause is the most common reason women experience hot flashes but they can occur due to other conditions, including:

• Breast cancer
• Chemotherapy-induced ovarian failure
• Estrogen-lowering medications
• Infertility medications (e.g., ovulation drugs)

Men can also experience hot flashes. These may be caused by androgen ablation therapy (often used in cancer treatment) or orchiectomy (surgical removal of a testicle).

Although hormone replacement therapy (HRT) is often recommended for frequent and severe hot flashes, these medications come with potentially serious side effects. Not all women are candidates for HRT based on a number of factors.

Women can take several steps to reduce the risk of experiencing hot flashes that do not include medication, such as exercising regularly and adjusting their diet. Herbal supplements, such as black cohosh, are not effective for reducing hot flashes, according to a large study conducted by the National Institutes of Health.

A sudden rush of heat from a woman’s chest to her head is called a hot flash. Hot flashes may be accompanied by heavy sweating and reddening of the head, neck and chest, or entire body. Hot flashes that occur at night when a woman is sleeping are referred to as night sweats as they commonly cause drenching sweats.

Hot flashes can range from a mild feeling of warmth to even, intense heat in the upper body. In some cases, they can be accompanied by:

• Flushed appearance
• Red, blotchy skin on the face, arms and neck
• A rapid heartbeat
• Mild to drenching perspiration
• A chilled feeling after the hot flashes pass

Most women find that hot flashes come in bursts that can last a few seconds or minutes, but some may last for up to 30 minutes. Hot flashes are frequently accompanied by profuse perspiration and sometimes heart palpations (rapid heart beat). Some women report feeling nauseous when they experience more intense hot flashes. They can occur several times an hour or just once or twice per day. When hot flashes occur at night (night sweats), they can wake a person from a sound sleep.

Hot flashes are most commonly associated with menopause, a change that occurs when a woman’s body no longer releases eggs, and her ovaries produce significantly lower amounts of the hormones estrogen and progesterone. As estrogen levels decline during this time, many women experience varying degrees of symptoms, including hot flashes.

Menopause typically occurs between the ages of 45 and 55 years, although it can occur earlier or later. Menopause is officially said to have occurred when a woman goes without a menstrual cycle (also known as a period) for 12 consecutive months and there are no other reasons for this change.

Although menopause usually occurs because of the natural aging process, other factors can trigger the event at younger ages, which in turn leads to hot flashes. Medical conditions that require surgery to remove both ovaries (bilateral oophorectomy) will cause premature menopause.

In addition, genetic factors and cancer treatments such as chemotherapy or radiation therapy to the pelvic area can cause early menopause. Chemical or surgically-induced menopause often causes severe hot flashes. Women requiring treatment with certain estrogen blockers for endometrial or breast cancer may also experience these symptoms.

There are about 37.5 million women reaching or currently at menopause (ages 40 to 59) in the United States, according to data collected as part of the U.S. census in 2000. According to the Food and Drug Administration (FDA), about 85 percent of women approaching or going through menopause have hot flashes. That roughly translates into nearly 32 million women experiencing hot flashes.

Many women experience hot flashes as a symptom of impending menopause during what is called a transitional period or perimenopause. Some women will have hot flashes for only a short time but the majority of women will have them for at least a year or more. There are women who go through perimenopause and menopause with no hot flashes.

Hot flashes are caused by changes in the way blood vessels relax and contract, and are typically associated with fluctuations in a woman’s estrogen levels. During the hot flash, the woman will suddenly feel her skin temperature begin to rise. Although she may initially feel quite warm, the heat lost by her body’s cooling mechanism (perspiration) will cause her core body temperature to drop below normal. For this reason, she may experience chills or even shivering afterward as the body attempts to restore a normal temperature.

The biological reasons for hot flashes are not completely understood. Most health experts believe that they are related to a decreasing level of estrogen, since hot flashes are most commonly linked to menopause. Hot flashes may be caused by fluctuating levels of other hormones that, in turn, affect the part of the brain (hypothalamus) that regulates body temperature. This process may cause the body to believe it is too hot even when it is a normal temperature. This signal tells the body to release the excess heat and it responds by dilating blood vessels in the head, face, neck and chest, causing a hot flash.

Hot flashes can be upsetting and frustrating for a woman, particularly if they are intense. However, there is no medical cause for concern as hot flashes are not a sign of a medical problem, but rather a normal biological reaction to fluctuating hormone levels in a woman’s body. Aside from menopause, hot flashes may be caused by breast cancer or its treatment.

Other factors that may contribute to hot flashes include:

• Chemotherapy-induced ovarian failure
• Estrogen-lowering medications
• Infertility medications (e.g., ovulation drugs)
  

Men can also experience hot flashes. Often the cause is either an infection or a side effect of certain medications. It can also be the result of undergoing androgen ablation therapy. It is considered fairly common among men treated for prostate cancer with GnRH agonists or by having their testicles removed. Physicians will often order a blood test to see if a testosterone deficiency is another reason for the hot flashes.

Hot flashes are closely related to other symptoms, particularly those of menopause. The most common symptoms related to hot flashes are:

• Night sweats (evening versions of “hot flashes”) and difficulty sleeping. Lack of sleep can contribute to women feeling tired, stressed or tense. In addition, severe hot flashes may increase the risk of insomnia, according to recent research.
  
  
• Irritability. In many cases, irritability accompanies sleep disturbances from nighttime hot flashes. However, not all women become irritable from disrupted sleep. Additionally, irritability may be a side effect of hormone replacement therapy.
  
  
• Other mood changes including mood swings and depression. Some researchers believe these emotions are a result of changes in the brain caused by a decrease in estrogen. Others think menopausal symptoms such as hot flashes, sleep problems and fatigue cause the feelings. Still others maintain that a combination of these factors is probably responsible.

Normally hot flashes begin during perimenopause, the years leading up to menopause. This is the time when estrogen levels begin to fluctuate. It is possible for hot flashes during perimenopause to be accompanied by mild to severe heart palpitations, anxiety or irritability.

Hot flashes are often more severe in women who experience premature menopause due to chemotherapy, antiestrogen treatment for breast cancer or surgical removal of the ovaries (oophorectomy). Premature ovarian failure (POF), which can be caused by factors such as genetics, smoking and autoimmune diseases, also results in premature menopause, which in turn, may cause hot flashes.

Other potential causes of hot flashes include:

• Hot weather
• Spicy foods
• Alcohol consumption
• Caffeine
• Stress
• Infertility medications (e.g., ovulation drugs)

The severity of hot flashes will vary from woman to woman, with some experiencing few or none. In most cases, hot flashes will gradually fade or disappear over time, with or without treatment.

Women experiencing hot flashes should notify their physician. To determine whether hot flashes are caused by menopause, the physician will perform a physical examination and compile a medical history of the patient. The physician may also perform a number of tests that may help reveal whether menopause has occurred. An individual can have certain hormones (FSH and LH) measured by a blood test. These hormones are associated with causing the release of estrogen and progesterone. When FSH and LH become elevated, it indicates that estrogen levels are low.

The Food and Drug Administration (FDA) states that women who have hot flashes less than seven times per day have “mild” symptoms, which may not require treatment. However, only an individual patient can determine if the frequency and intensity of hot flashes require treatment.

For women who are experiencing hot flashes as part of menopause, it is important to note that menopause is a natural part of aging and thus it is perfectly normal to elect no treatment at all for the hot flashes. In fact, the National Institutes of Health (NIH) has called for the “demedicalization” of menopause and its symptoms, including hot flashes. The NIH states that menopause is not a disease that always requires “treatment” since many women make the transition with few disabling symptoms and even moderate symptoms may not require medical intervention.

Although hot flashes are a normal part of perimenopause and menopause, severe or frequent hot flashes that disrupt a woman’s daily life or cause sleep disorders may require treatment. Before considering medical treatment, a woman may want to start by making healthy lifestyle choices as they can make a significant difference in the frequency and severity of hot flashes. These include quitting smoking, eating a well-balanced diet and getting regular exercise.

However, if these steps do not work, there are other steps to reduce the severity of symptoms, especially hot flashes, which are associated with this time of life. The most common form of treatment for hot flashes is hormone replacement therapy (HRT). This involves taking synthetic estrogen alone or a combination of estrogen and synthetic progesterone, known as progestin. HRT is associated with certain risks including blood clots, stroke, heart attacks, breast cancer and Alzheimer’s disease, and some women will be poor candidates for HRT. Therefore, women should consult with their physician prior to taking HRT.

Women who experience hot flashes during perimenopause (and who do not smoke) may want to consider low-dose oral contraceptives (birth control pills) since these can help control hot flashes and regulate the menstrual cycle. However, women who smoke, have a history of blood clots or breast cancer should not take birth control pills. This topic should be discussed with a physician.

In some cases, alternative medications can be taken to help reduce hot flashes, including short term, low dose estrogen, certain antidepressants (selective serotonin reuptake inhibitors [SSRIs]), blood pressure medications and the anticonvulsant gabapentin. However, a recent review of various studies found that non-hormonal therapies (e.g., SSRIs, blood pressure drugs, gabapentin) are less effective than estrogen therapy for alleviating hot flashes and often have side effects including nausea, dizziness, drowsiness, sexual dysfunction, imbalance when walking, leg swelling, dry mouth and constipation.

Some women may turn to herbal or dietary supplements (e.g., black cohosh, soy products) for alleviating their hot flashes and night sweats. However, a large year-long clinical trial funded by the NIH and published in late 2006 found black cohosh (whether used alone or with other herbal supplements) not effective for relieving hot flashes in postmenopausal women or those approaching menopause. Other forms of complementary and alternative medicine, such as acupuncture and massage therapy, may help induce relaxation, which in turn, may provide some relief for women who experience hot flashes. Although these are not considered medications, their use should be discussed with a physician.

In addition, an expert panel on menopause from the NIH cautioned women to be wary of studies with limited safety data. They concluded that to date, nothing has been proven to be as effective as estrogen therapy for alleviating hot flashes and additional research is needed.

There is currently no way to prevent hot flashes. Nor is there a method available that will predict when hot flashes will begin or how long they might last. Women can often reduce the frequency or severity of hot flashes by following these general guidelines:

• Exercise regularly. Try to get at least 30 minutes of exercise on most days of the week. In addition to helping maintain a healthy body weight, exercise can also reduce stress, which may cause hot flashes.
  
  
• Maintain a healthy weight. Women should maintain a weight deemed healthy by their physician. Several studies have suggested that a high body mass index may increase a woman’s severity and/or frequency of hot flashes, according to the American College of Obstetricians and Gynecologists (ACOG).
  
  
• Quit smoking. According to the ACOG, women who smoke have more severe and more frequent hot flashes compared to those who never smoked or who were former smokers. Additionally, the more a woman smokes, the greater the reported risk of having hot flashes.
  
  
• Eat a healthy diet. Women should eat plenty of whole-grain products, vegetables, fruits and soy products. Some health experts believe that increasing the number or amount of legumes consumed in the diet can help reduce hot flashes. Common foods that contain soy are tofu, tempeh, miso, soy milk, whole soybeans, texturized vegetable protein and soy powder. Certain products, such as chocolate or caffeinated beverages, may increase hot flashes in some women.
  
  
• Drink in moderation. Women should not have more than one alcoholic drink per day. Wine and other liquor has been known to increase hot flashes in women.
  
  
• Maintain a cool environment (drop thermostat and/or use a fan).
  
  
• Dress appropriately. Women who experience hot flashes may find relief by dressing in layers and wearing natural fabrics, such as cotton or silk that can “breathe” instead of polyester. Since chills may follow hot flashes, it is convenient to have clothing that can be easily added and removed.
  
  
• Practice relaxation techniques. Some women find that yoga, acupuncture and biofeedback help with hot flashes.

Hot flashes may also be reduced by avoiding spicy foods and foods or beverages containing caffeine. Good health and sound lifestyle choices can reduce the likelihood of symptoms. However most women will experience at least some ill effects associated with menopause.

Health experts from a wide variety of disciplines, including bioengineering, physiology and the behavioral sciences are conducting ongoing research to not only understand the causes of hot flashes, but possibly find a better way to collect data and measure the hot flashes. This in turn should help experts better determine which treatments work and which do not.

Some of the current research that is being conducted by the National Institutes of Health (NIH) includes:

• A better understanding of the physical processes that lead to hot flashes
  
  
• Ways to improve the sterna skin conductance systems (which measure the rise in skin temperature during a hot flash)
  
  
• The development of additional tools to identify hot flashes
  
  
• A better system for collection of data from women enrolled in clinical trials that use diaries or questionnaires on hot flash frequency
  
  
• Better means for collecting information on the intensity and interference with a woman’s daily activities
  
  
• The development of animal models of hot flashes to test complimentary and alternative medicines that have been proposed to manage hot flashes

Other studies hope to determine why, unlike in the United States, hot flashes are uncommon in certain parts of the world. Research is focusing on explaining which environmental factors in the United States may cause a higher incidence of hot flashes.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor or other healthcare professional the following questions about hot flashes:

1. Are my symptoms related to menopause?
   
   
2. How do I know if I’m in menopause?
   
   
3. How long might I have these symptoms?
   
   
4. Can certain things trigger the hot flashes?
   
   
5. Is there anything I could be doing that is making the hot flashes worse?
   
   
6. Is there something I can do to reduce their intensity or eliminate them altogether?
   
   
7. Should I take hormone replacement therapy (HRT) to reduce my hot flashes?
   
   
8. Are there other medications that I could take in place of HRT, or in addition to it?
   
   
9. Are there any alternative therapies that will help?
   
   
10. Are hot flashes hereditary?

Some physicians recommend keeping a diary of hot flashes, including their frequency and severity. Patients may want to use the following table as a guide and then discuss the results with their healthcare provider:

* How bothersome is this symptom from 1 (not at all) to 5 (very much)?