A hot flash is a feeling of warmth spreading over the body that is often most strongly felt in the head and neck regions. Hot flashes may be accompanied by perspiration or flushing and usually last from 30 seconds to several minutes. Although hot flashes are a characteristic symptom of perimenopause, rare tumors, and other medical conditions may sometimes also cause hot flashes. Taking certain medications, eating spicy foods, and the consumption of alcohol have also been associated with the occurrence of hot flashes.
Although the exact cause of hot flashes is not fully understood, hot flashes that occur in perimenopause are thought to be due to a combination of hormonal and biochemical fluctuations brought on by declining estrogen levels. Hot flashes can often begin before the menstrual irregularities characteristic of menopause is even noticed. Up to 40% of regularly menstruating women in their 40s report to have hot flashes. Hot flashes can sometimes be accompanied by night sweats (episodes of drenching sweats occurring at nighttime).