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Hot flashes (American English) or hot flushes (British English) are a form of flushing due to reduced levels of estradiol. Hot flashes are a symptom which may have several other causes, but which is often caused by the changing hormone levels that are characteristic of menopause. They are typically experienced as a feeling of intense heat with sweating and rapid heartbeat, and may typically last from 2 to 30 minutes for each occurrence.
Signs and symptoms
Hot flashes, a common symptom of menopause and perimenopause, are typically experienced as a feeling of intense heat with sweating and rapid heartbeat, and may typically last from two to thirty minutes for each occurrence, ending just as rapidly as they began. The sensation of heat usually begins in the face or chest, although it may appear elsewhere such as the back of the neck, and it can spread throughout the whole body. Some women feel as if they are going to faint. In addition to being an internal sensation, the surface of the skin, especially on the face, becomes hot to the touch. This is the origin of the alternative term "hot flush", since the sensation of heat is often accompanied by visible reddening of the face. Excessive flushing can lead to rosacea.
The hot-flash event may be repeated a few times each week or every few minutes throughout the day. Hot flashes may begin to appear several years before menopause starts and last for years afterwards. Some women undergoing menopause never have hot flashes. Others have mild or infrequent flashes. The worst sufferers experience dozens of hot flashes each day. In addition, hot flashes are often more frequent and more intense during hot weather or in an overheated room, the surrounding heat apparently making the hot flashes themselves both more likely to occur, and more severe.
Severe hot flashes can make it difficult to get a full night's sleep (often characterized as insomnia), which in turn can affect mood, impair concentration, and cause other physical problems. When hot flashes occur at night, they are called "night sweats". As estrogen is typically lowest at night, some women get night sweats without having any hot flashes during the daytime.
If hot flashes occur at other times in a young woman's menstrual cycle, then it might be a symptom of a problem with her pituitary gland; seeing a doctor is highly recommended. In younger women who are surgically menopausal, hot flashes are generally more intense than in older women, and they may last until natural age at menopause.
Hot flashes in men could have various causes. It can be a sign of low testosterone.[medical citation needed] Men with prostate cancer or testicular cancer can also have hot flashes, especially those who are undergoing hormone therapy with antiandrogens, also known as androgen antagonists, which reduce testosterone to castrate levels. Men who are castrated can also get hot flashes.
Some menopausal women may experience both standard hot flashes and a second type sometimes referred to as "slow hot flashes" or "ember flashes". The standard hot flash comes on rapidly, sometimes reaching maximum intensity in as little as a minute. It lasts at full intensity for only a few minutes before gradually fading.
Slow "ember" flashes appear almost as quickly but are less intense and last for around half an hour. Women who experience them may undergo them year round, rather than primarily in the summer, and ember flashes may linger for years after the more intense hot flashes have passed.
Research on hot flashes is mostly focused on treatment options. The exact cause and pathogenesis, or causes of vasomotor symptoms (VMS)—the clinical name for hot flashes—has not yet been fully studied. There are hints at reduced levels of estrogen as the primary cause of hot flashes. There are indications that hot flashes may be due to a change in the hypothalamus's control of temperature regulation.
Transgender men on hormone blockers to halt their female puberty also commonly experience hot flashes, because hormone blockers simulate or induce menopause.
Hormone replacement therapy
Hormone replacement therapy may relieve many of the symptoms of menopause. However, oral HRT may increase the risk of breast cancer, stroke, and dementia and has other potentially serious short-term and long-term risks. Since the incidence of cardiovascular disease in women has shown a rise that matches the increase in the number of post menopausal women, recent studies have examined the benefits and side effects of oral versus transdermal application of different estrogens and found that transdermal applications of estradiol may give the vascular benefits lowering the incidences of cardiovascular events with less adverse side effects than oral preparations.
Women who experience troublesome hot flashes are advised by some to try alternatives to hormonal therapies as the first line of treatment. If a woman chooses hormones, they suggest she take the lowest dose that alleviates her symptoms for as short a time as possible. The US Endocrine Society concluded that women taking hormone replacement therapy for 5 years or more experienced overall benefits in their symptoms including relief of hot flashes and symptoms of urogenital atrophy and prevention of fractures and diabetes.
When estrogen as estradiol is used transdermally as a patch, gel, or pessary with micronized progesterone this may avoid the serious side effects associated with oral estradiol HRT since this avoids first pass metabolism (Phase I drug metabolism). Women taking bioidentical estrogen, orally or transdermally, who have a uterus must still take a progestin or micronized progesterone to lower the risk of endometrial cancer. A French study of 80,391 postmenopausal women followed for several years concluded that estrogen in combination with micronized progesterone is not associated with an increased risk of breast cancer. The natural, plant-derived progesterone creams sold over the counter contain too little progesterone to be effective. Wild yam (Dioscorea villosa) extract creams are not effective since the natural progesterone present in the extract is not bioavailable.
Selective serotonin reuptake inhibitors
SSRIs are a class of pharmaceuticals that are most commonly used in the treatment of depression. They have been found efficient in alleviating hot flashes. On 28 June 2013 FDA approved Brisdelle (low-dose paroxetine mesylate) for the treatment of moderate-to-severe vasomotor symptoms (e.g. hot flashes and night sweats) associated with menopause. Paroxetine became the first and only non-hormonal therapy for menopausal hot flashes approved by FDA.
Clonidine is a blood pressure-lowering medication that can be used to relieve menopausal hot flashes when hormone replacement therapy is not needed or not desired. For hot flashes, clonidine works by helping reduce the response of the blood vessels to stimuli that cause them to narrow and widen. While not all women respond to clonidine as a hot flash medication, it can reduce hot flashes by 40% in some peri-menopausal women.
Isoflavones are commonly found in legumes such as soy and red clover. The two soy isoflavones implicated in relieving menopausal symptoms are genistein and daidzein, and are also known as phytoestrogens. The half life of these molecules is about eight hours, which might explain why some studies have not consistently shown effectiveness of soy products for menopausal symptoms. Although red clover (Trifolium pratense) contains isoflavones similar to soy, the effectiveness of this herb for menopausal symptoms at relatively low concentrations points to a different mechanism of action.
- Ginseng: Very few studies exist on the effect of ginseng for relief of menopausal symptoms. In a large double-blinded randomized controlled trial, reduction in hot flashes was not statistically significant but showed a strong trend towards improvement. Lack of statistical significance suggests future research, but does not meet the scientific bar for ginseng to be deemed effective.
- Flaxseed: There have also been several clinical trials using flaxseed. Flaxseed is the richest source of lignans, which is one of three major classes of phytoestrogen. Lignans are thought to have estrogen agonist and antagonist effects as well as antioxidant properties. Flaxseed and its lignans may have potent anti-estrogenic effects on estrogen receptor positive breast cancer and may have benefits in breast cancer prevention efforts. One recent study done in France, looked at four types of lignans, including that found in flaxseed (Secoisolariciresinol) in a prospective cohort study to see if intake predicted breast cancer incidence. The authors report lowered risk of breast cancer among over 58,000 postmenopausal women who had the third highest quartile of lignan intake. There have been a few small pilot studies that have tested the effect of flaxseed on hot flashes. Currently there is a large study sponsored by the National Cancer Institute that is ongoing, but not accepting any new participants. The rationale for the study is that estrogen can relieve the symptoms of menopause, but can also cause the growth of breast cancer cells. Flaxseed may reduce the number of hot flashes and improve mood and quality of life in postmenopausal women not receiving estrogen therapy.
- University of Glasgow (24 October 2007). "Doctors seek the key to understanding hot flushes". University News (Archive of news). University of Glasgow. Retrieved 19 April 2013.
- About.com (n.d.). "Menopause". About.com. Archived from the original on 2011-03-09. Retrieved 19 April 2013.
- Bunyavanich, Supinda (6 June 2007). "Low Testosterone Could Kill You". ABC News. ABC News Internet Ventures. Retrieved 20 April 2013.
- "What to Expect During Therapy". Lupron Depot. Abbott Laboratories. Retrieved 20 April 2013.
- "Hot Flashes In Men -- Mayo Clinic Researchers Describe A Treatment". ScienceDaily. Science Daily LLC. 19 October 2004. Retrieved 20 April 2013.
- Engstrom, Christine A.; Kasper, Christine E. (March 2007). "Physiology and Endocrinology of Hot Flashes in Prostate Cancer". American Journal of Men's Health. 1 (1): 8–17. doi:10.1177/1557988306294162. PMID 19482779. Retrieved 20 April 2013.
- Anitei, Stefan (16 April 2007). "Men Can Experience Hot Flashes, Just Like Women in Menopause". Softpedia. Softpedia. Retrieved 20 April 2013.
- Utian, Wulf H. (2012-06-01). "Recent Developments in Pharmacotherapy for Vasomotor Symptoms". Current Obstetrics and Gynecology Reports. 1 (2): 43–49. doi:10.1007/s13669-012-0009-4. ISSN 2161-3303. Retrieved 17 April 2013.
- Shanafelt, Tait D.; Barton, Debra L.; Adjei, Alex A.; Loprinzi, Charles L. (November 2002). "Pathophysiology and Treatment of Hot Flashes". Mayo Clinic Proceedings. 77 (11): 1207–1218. doi:10.4065/77.11.1207. PMID 12440557.
- Linda Gannon (1985). Menstrual Disorders and Menopause: Biological, Psychological, and Cultural Research. Praeger. ISBN 978-0-03-003878-5. Retrieved 19 April 2013.
- Anna-Clara, Spetz; Zetterlund, Eva-Lena; Varenhorst, Eberhard; Hammar, Mats (November–December 2003). "Incidence and Management of Hot Flashes in Prostate Cancer" (PDF). The Journal of Supportive Onocology. 1 (4): 263–273. Retrieved 19 April 2013.
- Roberta Brinton; et al. (Nov 15, 2016). "Mechanistic role of brain hypometabolism and mitochondrial uncoupling in perimenopausal hot flash". abstractsonline.com.
- U.S. Food and Drug Administration (10 February 2004). "FDA Updates Hormone Therapy Information for Post Menopausal Women". FDA News Release (Archived content). U.S. Food and Drug Administration. Retrieved 19 April 2013.
- Rossouw, Jacques E. (July 2002). "Risks and Benefits of Estrogen Plus Progestin in Healthy Postmenopausal Women". JAMA. 288 (3): 321–3. doi:10.1001/jama.288.3.321. PMID 12117397. Retrieved 21 September 2014.
- Serock, Michelle R. (Nov 2008). "Modulators of vascular sex hormone receptors and their effects in estrogen-deficiency states associated with menopause". Recent Patents on Cardiovascular Drug Discovery. 3 (3): 165–86. doi:10.2174/157489008786263970. PMID 18991792. Retrieved 29 September 2014.
- Løkkegaard, Ellen (Nov 2008). "Hormone therapy and risk of myocardial infarction: a national register study". European Heart Journal. 29 (21): 2660–8. doi:10.1093/eurheartj/ehn408. PMID 18826989. Retrieved 29 September 2014.
- "For Women - Menopause and Hormones: Common Questions".
- Santen, Richard J. (July 2010). "Postmenopausal Hormone Therapy: An Endocrine Society Scientific Statement". Journal of Clinical Endocrinology and Metabolism. 9 (7): s1–s66. doi:10.1210/jc.2009-2509. PMID 20566620.
- L'Hermite, M (Aug 2013). "HRT optimization, using transdermal estradiol plus micronized progesterone, a safer HRT". Climacteric : The Journal of the International Menopause Society. 16 Suppl 1: 44–53. doi:10.3109/13697137.2013.808563. PMID 23848491.
- Fournier, Agnès (March 2008). "Use of Different Postmenopausal Hormone Therapies and Risk of Histology- and Hormone Receptor–Defined Invasive Breast Cancer". Journal of Clinical Oncology. 26 (8): 1260–8. doi:10.1200/jco.2007.13.4338. PMC 2346534. PMID 18323549. Retrieved 29 September 2014.
- Harvard Women’s Health Watch (August 2006). "What are bioidentical hormones?". Harvard Women’s Health Watch. Harvard Women’s Health Watch. Retrieved 20 September 2014.
- Sicat, BL; Brokaw, DK (January 2004). "Nonhormonal alternatives for the treatment of hot flashes". Pharmacotherapy. 24 (1): 79–93. doi:10.1592/phco.126.96.36.199812. PMID 14740790.
- Food and Drug Administration (28 June 2013). "FDA NEWS RELEASE: FDA approves the first non-hormonal treatment for hot flashes associated with menopause". FDA.
- "Apo-Clonidine - Uses, Side Effects, Interactions - Drug Factsheets - C-Health". chealth.canoe.com. Retrieved 2015-12-21.
- "What Patients Need to Know About Hot Flashes". Medscape. (subscription required)
- Nissan Hani P.; Lu Jian; Booth Nancy L.; Yamamura Henry I.; Farnsworth Norman R.; Wan Z. Jim (2007). "A red clover (Trifolium pratense) phase II clinical extract possesses opiate activity". Journal of Ethnopharmacology. 112 (1): 207–210. doi:10.1016/j.jep.2007.02.006. PMID 17350196.
- Wiklund IK, Mattsson LA, Lindgren R, Limoni C (1999). "Effects of a standardized ginseng extract on quality of life and physiological parameters in symptomatic post-menopausal women: a double-blind, placebo-controlled trial". Int J Clin Pharmacol Res. 19 (3): 89–99. PMID 10761538.
- Basch E, Bent S, Collins J, et al. (2007). "Flax and flaxseed oil (Linum usitatissimum): a review by the Natural Standard Research Collaboration". J Soc Integr Oncol. 5 (3): 92–105. doi:10.2310/7200.2007.005. PMID 17761128.
- Jugenström, Malin Bergman; Thompson, Lilian U.; Dabrosin, Charlotta (1 February 2007). "Flaxseed and Its Lignans Inhibit Estradiol-Induced Growth, Angiogenesis, and Secretion of Vascular Endothelial Growth Factor in Human Breast Cancer Xenografts In vivo". Clinical Cancer Research. 13 (3): 1061–1067. doi:10.1158/1078-0432.CCR-06-1651. PMID 17289903.
- Touillaud, Marina S.; Thiébaut, Anne C. M.; Fournier, Agnès; Niravong, Maryvonne; Boutron-Ruault, Marie-Christine; Clavel-Chapelon, Françoise (21 March 2007). "Dietary Lignan Intake and Postmenopausal Breast Cancer Risk by Estrogen and Progesterone Receptor Status". Journal of the National Cancer Institute. 99 (6): 475–486. doi:10.1093/jnci/djk096. ISSN 1460-2105. PMC 2292813. PMID 17374837. Retrieved 20 April 2013.
- "Flaxseed in Treating Postmenopausal Women With Hot Flashes Who Have a History of Breast Cancer or Other Cancer or Who Do Not Wish to Take Estrogen Therapy". ClinicalTrials.gov. U.S. National Institute of Health. November 2010. Retrieved 20 April 2013.
- Frisk, Jessica W.; Hammar, Mats L.; Ingvar, Martin; Spetz Holm, Anna-Clara E. (30 January 2014). "How long do the effects of acupuncture on hot flashes persist in cancer patients?". Supportive Care in Cancer. 22 (5): 1409–1415. doi:10.1007/s00520-014-2126-2. PMID 24477325.
- MS Lee; KH Kim; BC Shin; E Ernst (July 2009). "Acupuncture for treating hot flushes in men with prostate cancer: a systematic review". Supportive Care in Cancer. 17 (7): 763–70. doi:10.1007/s00520-009-0589-3. PMID 19224253.
- Messina, Mark; Claude Hughes (2003). "Efficacy of Soyfoods and Soybean Isoflavone Supplements for Alleviating Menopausal Symptoms Is Positively Related to Initial Hot Flush Frequency". Journal of Medicinal Food. 6 (1): 1–11. doi:10.1089/109662003765184697. PMID 12804015.
- Lock, Margaret (May–August 1994). "Menopause in cultural context". Experimental Gerontology. 29 (3–4): 307–317. doi:10.1016/0531-5565(94)90011-6. PMID 7925751.