Vasomotor symptoms (VMS)
Also called hot flashes, hot flushes, night sweats
Reviewed August 2026 against NHS, NIH and WHO references.
In short
Vasomotor symptoms, or VMS, is the medical name for hot flashes and night sweats. They are sudden waves of heat, flushing and sweating caused by changes in the brain's temperature control as estrogen falls. VMS is the most common reason women seek help in perimenopause and can last for years.
Hot flashes and night sweats, by their clinical name
If a form or a doctor mentions 'vasomotor symptoms' or VMS, they mean hot flashes and night sweats. A hot flash is a sudden feeling of heat through the face, neck and chest, often with flushing, sweating and a racing heart, then a chill. When they happen in sleep and soak the sheets, they are called night sweats.
Why they happen
As estrogen falls, the part of the brain that regulates body temperature becomes more sensitive. The range of temperatures it treats as comfortable narrows, so a small rise makes the body react as if it is overheating: it flushes and sweats to cool down. The hormone change, not the room, is the trigger.
How common, and how long
Vasomotor symptoms are the most common reason women seek help in perimenopause. They can begin before periods stop and, for many, continue for several years afterward. They range from mild and occasional to frequent and disruptive, and effective treatments exist, both hormonal and non-hormonal.
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Related terms
Sources
This definition is for general information only and is not medical advice. Menopause care depends on your individual health history. Please talk to a qualified clinician about what is right for you.