PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Hot flushes are due to vasomotor instability and are usually related to the female menopause.
Hot flushes are thought to be related to changes in central nervous system neurotransmitters and peripheral vascular reactivity. There is still much that is not understood. The aetiology of hot flushes in menopause would seem to be related to low oestrogen levels as the ovaries fail, and the effect on central thermoregulation.
They do not tend to occur in men, as there is not a similar rapid decline in hormones. However, treatment for prostate cancer that involves suppression of testosterone production can produce a picture similar to menopausal hot flushes in women and can be just as severe.
- Reported prevalence varies greatly between studies.
- Most studies agree that hot flushes and night sweats substantially increase in frequency and severity during the menopausal transition.
- These symptoms are experienced by 70-80% of menopausal women.
- They are most common in the first year following the last menstruation.
- Hot flushes usually last for 2-5 years, although some women may continue to experience symptoms for much longer.
- Most women (90%) manage symptoms without seeking professional advice.
- They tend to be more severe in women of low body weight, those who take little or no exercise and those who smoke cigarettes.
- There is variation in frequency and duration between different races. Japanese women seem to have a particularly low incidence of hot flushes. In the USA, women of Afro-Caribbean origin have been shown to have flushes which last for more years than those of white women.
- An abrupt or early menopause causes more severe symptoms. Thus, surgical oophorectomy or its equivalent induced with chemotherapy, radiation or drugs produces more pronounced symptoms than a natural menopause.
- Hot flushes may last between a few seconds and 10 minutes but an average is around 4 minutes. Frequency may be from every hour to a couple of times a week.
- There is a sensation of intense heat and a feeling that the face and whole body is flushing. It is often difficult to ignore and women having hot flushes often fling open windows when all around them are anything but warm. Flushing and sweating may not be apparent to the observer but the person affected tends to be very self-conscious of the affliction.
- Lack of concentration and poor memory are commonly associated.
- Sleep disturbance is common with night sweats. Features of depression are not unusual.
- Frequent flushes and disturbance of sleep may well be a major contributor to the commonly observed adverse effect on mood. There is evidence that the sex hormones do have an effect on mood and well-being in both men and women. Hormone replacement therapy (HRT) improves fatigue, depression, headaches and libido in men as well as in women.
- Inappropriate vasodilatation leads to a slight drop in core temperature. Between attacks there is no abnormality to be found.
Other causes of flushing to consider:
- Carcinoma of the pancreas.
- Carcinoid tumours.
- Phaeochromocytoma (may be part of a multiple endocrine neoplasia syndrome).
- Brain tumours and spinal cord lesions (can lead to vasomotor instability).
- Panic disorder.
- Frey's syndrome (flushing when the affected person eats, sees, thinks about or talks about certain kinds of food which produce strong salivation; may occur as a complication of parotid gland surgery).
- Some food substances - eg, monosodium glutamate.
- Some drugs - for example:
- Calcium-channel blockers.
- Selective serotonin reuptake inhibitors (SSRIs).
- Selective (o)estrogen receptor modulators (SERMS) such as raloxifene and tamoxifen.
- Anti-androgens such as cyproterone, spironolactone, bicalutamide, 5-alpha-reductase inhibitors.
- There may be a history of menstruation becoming irregular or ceasing but not necessarily. There may have been surgery, radiotherapy or chemotherapy, involving removal or inactivation of the ovaries. Similar causes of sudden withdrawal of sex hormones in men produce a similar response.
- If there is doubt about the diagnosis then oestrogen levels (or testosterone in men) will be low and follicle-stimulating hormone (FSH) and luteinising hormone (LH) will be raised. Levels fluctuate, so it may be necessary to obtain more than one blood sample to confirm the elevated gonadotrophins.
Hot flushes do not threaten life but they can have a marked effect on the quality of life. They will subside with time but a sympathetic and positive approach is required.
The following lifestyle advice should be given:
- Take regular exercise - but note exercise has not been proven to improve symptoms to date.
- Weight loss in overweight women may improve symptoms.
- Wear lighter-weight clothing and sleep in a cooler room.
- Avoid possible triggers, such as spicy foods, caffeine, smoking, stress and alcohol.
This is the most effective form of treatment but concern over long-term safety has reduced its popularity with both doctors and patients. The necessary duration of treatment is very variable but may be months or often years. See separate Hormone Replacement Therapy (including Risks and Benefits) article for details.
Alternative treatments to HRT
- SSRI antidepressants, which seem to be effective - for example, paroxetine (20 mg daily), fluoxetine (20 mg daily), citalopram (20 mg daily), or venlafaxine 37.5 mg twice a day (unlicensed).
- Clonidine 50-75 micrograms twice a day (licensed use) probably does work, although evidence is limited; side-effects, however, can be a problem. A trial of 2-4 weeks is required.
- A progestogen - eg, norethisterone or megestrol (unlicensed). Royal College of Obstetricians and Gynaecologists (RCOG) guidelines advise against this in view of safety concerns in menopausal women. However, National Institute for Health and Care Excellence (NICE) guidelines recommend a trial of medroxyprogesterone 10 mg twice a day for 10 weeks in men with hot flushes due to hormone therapy for prostate cancer. Cyproterone or megestrol is advised as second-line.
- The anticonvulsant gabapentin is also effective. Divided doses of 600-2400 mg per day are used.
- Phyto-oestrogens, usually derived from soya or red clover, have been used. A Cochrane review in 2013 found no conclusive evidence of efficacy.
- Many other herbal remedies have been used but vigorous trials tend to show little or no benefit. The latest Cochrane review on the use of black cohosh for hot flushes found no evidence to support its use; however, it did conclude there was justification for further study.
- As a non-hormonal treatment, beta-blockers were once popular but have been shown to be ineffective and are no longer advised.
- There is little evidence to support the use of acupuncture or relaxation techniques.
Further reading & references
- Archer DF, Sturdee DW, Baber R, et al; Menopausal hot flushes and night sweats: where are we now? Climacteric. 2011 Oct;14(5):515-28. doi: 10.3109/13697137.2011.608596. Epub 2011 Aug 18.
- Menopause; NICE CKS, June 2013 (UK access only)
- Freeman EW, Sammel MD, Lin H, et al; Duration of menopausal hot flushes and associated risk factors. Obstet Gynecol. 2011 May;117(5):1095-104. doi: 10.1097/AOG.0b013e318214f0de.
- Daley A, Stokes-Lampard H, Thomas A, et al; Exercise for vasomotor menopausal symptoms. Cochrane Database Syst Rev. 2014 Nov 28;11:CD006108. doi: 10.1002/14651858.CD006108.pub4.
- Gurney EP, Nachtigall MJ, Nachtigall LE, et al; The Women's Health Initiative trial and related studies: 10 years later: a clinician's view. J Steroid Biochem Mol Biol. 2014 Jul;142:4-11. doi: 10.1016/j.jsbmb.2013.10.009. Epub 2013 Oct 27.
- Marjoribanks J, Farquhar C, Roberts H, et al; Long term hormone therapy for perimenopausal and postmenopausal women. Cochrane Database Syst Rev. 2012 Jul 11;7:CD004143. doi: 10.1002/14651858.CD004143.pub4.
- Alternatives to HRT for management of symptoms of menopause; Royal College of Obstetricians and Gynaecologists (September 2010)
- Prostate cancer: diagnosis and treatment; NICE Clinical guideline (Jan 2014)
- Hayes LP, Carroll DG, Kelley KW; Use of gabapentin for the management of natural or surgical menopausal hot flashes. Ann Pharmacother. 2011 Mar;45(3):388-94. doi: 10.1345/aph.1P366. Epub 2011 Feb 22.
- Lethaby A, Marjoribanks J, Kronenberg F, et al; Phytoestrogens for menopausal vasomotor symptoms. Cochrane Database Syst Rev. 2013 Dec 10;12:CD001395. doi: 10.1002/14651858.CD001395.pub4.
- Leach MJ, Moore V; Black cohosh (Cimicifuga spp.) for menopausal symptoms. Cochrane Database Syst Rev. 2012 Sep 12;9:CD007244. doi: 10.1002/14651858.CD007244.pub2.
- Dodin S, Blanchet C, Marc I, et al; Acupuncture for menopausal hot flushes. Cochrane Database Syst Rev. 2013 Jul 30;7:CD007410. doi: 10.1002/14651858.CD007410.pub2.
- Saensak S, Vutyavanich T, Somboonporn W, et al; Relaxation for perimenopausal and postmenopausal symptoms. Cochrane Database Syst Rev. 2014 Jul 20;7:CD008582. doi: 10.1002/14651858.CD008582.pub2.
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Dr Colin Tidy
Dr Mary Harding
Prof Cathy Jackson