A hot flash, sometimes called a hot flush, is a quick feeling of heat and usually causes a red, flushed face and sweating of the face and scalp. The exact cause of hot flashes is not known, but may be related to changes in circulation. Hot flashes happen when the blood vessels near the skin’s surface dilate to cool. Some women have a rapid heart rate, anxiety, and eventually chills.Continue reading below… Hot flashes with sweating can also happen at night. These are called night sweats and may make it harder to sleep because they wake up hot and sweaty. This may happen multiple times per night. Hot flashes vary among women going through menopause. Some women have hot flashes for a very short time during menopause. Other women may have hot flashes for life. Generally, hot flashes are less severe as time passes.