Overview

A hot flash is the sudden feeling of warmth in the upper body, which is usually most intense over the face, neck and chest. Your skin might redden, as if you're blushing. A hot flash can also cause sweating. If you lose too much body heat, you might feel chilled afterward. Night sweats are hot flashes that happen at night, and they may disrupt your sleep.

Although other medical conditions can cause them, hot flashes most commonly are due to menopause — the time when menstrual periods become irregular and eventually stop. In fact, hot flashes are the most common symptom of the menopausal transition.

There are a variety of treatments for bothersome hot flashes.

Symptoms

During a hot flash, you might have:

  • A sudden feeling of warmth spreading through your chest, neck and face
  • A flushed appearance with red, blotchy skin
  • Rapid heartbeat
  • Perspiration, mostly on your upper body
  • A chilled feeling as the hot flash lets up
  • Feelings of anxiety

The frequency and intensity of hot flashes vary among women. Hot flashes may be mild or so intense that they disrupt daily activities. They can happen at any time of day or night. Nighttime hot flashes (night sweats) may wake you from sleep and can cause long-term sleep disruptions.

How often hot flashes occur varies among women, but most women who report having hot flashes experience them daily. On average, hot flash symptoms persist for more than seven years. Some women have them for more than 10 years.

When to see a doctor

If hot flashes affect your daily activities or nighttime sleep, consider seeing your doctor to discuss treatment options.

Causes

Hot flashes are most commonly caused by changing hormone levels before, during and after menopause. It's not clear exactly how hormonal changes cause hot flashes. But most research suggests that hot flashes occur when decreased estrogen levels cause your body's thermostat (hypothalamus) to become more sensitive to slight changes in body temperature. When the hypothalamus thinks your body is too warm, it starts a chain of events — a hot flash — to cool you down.

Rarely, hot flashes and nights sweats are caused by something other than menopause. Other potential causes include medication side effects, problems with your thyroid, certain cancers and side effects of cancer treatment.

Risk factors

Not all women who go through menopause have hot flashes, and it's not clear why some women do have them. Factors that may increase your risk include:

  • Smoking. Women who smoke are more likely to get hot flashes.
  • Obesity. A high body mass index (BMI) is associated with a higher frequency of hot flashes.
  • Race. More black women report having hot flashes during menopause than do women of other races. Hot flashes are reported least frequently in Asian women.

Complications

Hot flashes may impact your daily activities and quality of life. Nighttime hot flashes (night sweats) can wake you from sleep and, over time, can cause long-term sleep disruptions.

Research suggests that women who have hot flashes may have an increased risk of heart disease and greater bone loss than women who do not have hot flashes.